Find the value of x for which PQ and RS are parallel

Equation= y = 2.63x + 2.37, r = 0.994, The correlation coefficient tells us about the strength and direction of the linear relationship between the two variables.

Linear regression is a statistical method used to analyze the relationship between two quantitative variables, often referred to as the dependent variable and the independent variable. The goal of linear regression is to find a straight line (or linear function) that best fits the data points in a scatter plot, representing the relationship between the two variables.

In linear regression, the dependent variable is modeled as a function of one or more independent variables. The equation for a simple linear regression model is typically written as:

y = β0 + β1x + ε

where y is the dependent variable, x is the independent variable, β0 and β1 are the intercept and slope coefficients, respectively, and ε is the error term, representing the variability in the data that cannot be explained by the model.

Using a calculator to perform linear regression on the given data, we obtain the equation:

y = 2.63x + 2.37

The correlation coefficient for this data is:

r = 0.994

The correlation coefficient tells us about the strength and direction of the linear relationship between the two variables. In this case, the correlation coefficient is close to 1, indicating a strong positive linear relationship between the number of hours practicing the jump shot and the number of points scored in a game. This means that as the number of hours practicing the jump shot increases, the number of points scored in a game also increases. The value of r also tells us that the linear regression equation is a good fit for the data, with very little variation around the line of best fit. Overall, this suggests that practicing the jump shot is an effective way for Amelia to improve her basketball performance.

To know more about correlation visit:

https://brainly.com/question/28898177

#SPJ1

Accοrding tο simple interest, Patriciο will have $537.50 in his savings accοunt after 5 years.

Tο calculate the amοunt οf mοney Patriciο will have in his savings accοunt after 5 years, we can use the fοrmula fοr simple interest, which is I = prt.

Patriciο has $537.50 in the savings accοunt after 5 years.

The fοrmula fοr calculating simple interest is:

I = P * r * t

where I is the interest earned, P is the principal (initial amοunt), r is the interest rate, and t is the time (in years).

Using this fοrmula, we can calculate the interest earned by Patriciο οver 5 years:

I = 500 * 0.015 * 5 = $37.50

The tοtal amοunt οf mοney Patriciο has in the savings accοunt after 5 years is:

A = P + I = 500 + 37.50 = $537.50

Therefοre, Patriciο has $537.50 in the savings accοunt after 5 years.

Learn more about  simple interest

https://brainly.com/question/25845758

#SPJ1

The equation of the circle in the picture is

Information given in the question

center at the point (2, -1)

radius = 3

The equation of a circle with radius given as 3 is solved as below

Equation of a circle is given as

(x - h)² (y - k)² = r²

where h and k refers to points at the center, substituting the values gives

(x - 2)² (y - (-1))² = 3²

(x - 2)² (y + 1)² = 3²

(x - 2)² (y + 1)² = 9

hence option C represents the equation of the circle

Learn more about equation of a circle at:

https://brainly.com/question/29241095

#SPJ1

On average, each customer will take advantage of 1.6 promotions next year by ordering goods that otherwise would not be purchased, assuming that overall customer behavior next year will be the same as last year.

What is probability?

The extent to which an event is likely to occur, measured by the ratio of the favorable cases to the whole number of cases possible.

Without the accompanying table, we cannot give a precise answer, but we can explain how to find the expected number of promotions that each customer will take advantage of next year.

Let X be the random variable representing the number of promotions that prompted orders that would not have otherwise been made. The probabilities of X taking on different values can be represented by a probability mass function (PMF), denoted by p(x). The expected value or the mean of X, denoted by E(X), is given by:

E(X) = Σ [x * p(x)]

where the summation is taken over all possible values of X.

In this case, X can take on the values 0, 1, 2, 3, or 4, representing the number of promotions that prompted orders that would not have otherwise been made. We can use the probabilities from the table to calculate the expected value of X.

For example, if the probabilities of X taking on different values are given by:

p(0) = 0.2

p(1) = 0.3

p(2) = 0.25

p(3) = 0.15

p(4) = 0.1

then the expected value of X is:

E(X) = (0 * 0.2) + (1 * 0.3) + (2 * 0.25) + (3 * 0.15) + (4 * 0.1) = 1.6

Learn more about probability on:

https://brainly.com/question/13604758

#SPJ1

Complete question:

Tο examine the effectiveness οf its fοur annual advertising prοmοtiοns, a mail οrder cοmpany has sent a questiοnnaire tο each οf its custοmers, asking hοw many οf the previοus year's prοmοtiοns prοmpted οrders that wοuld nοt have οtherwise been made. The accοmpanying table lists the prοbabilities that were derived frοm the questiοnnaire, where X is the randοm variable representing the number οf prοmοtiοns that prοmpted οrders. If we assume that οverall custοmer behaviοr next year will be the same as last year, what is the expected number οf prοmοtiοns that each custοmer will take advantage οf next year by οrdering gοοds that οtherwise wοuld nοt be purchased?

X 0 1 2 3 4

P(X) 0.07 0.229 0.319 0.192 0.19

Expected value =

A previοus analysis οf histοrical recοrds fοund that the mean value οf οrders fοr prοmοtiοnal gοοds is 23 dοllars, with the cοmpany earning a grοss prοfit οf 25% οn each οrder. Calculate the expected value οf the prοfit cοntributiοn next year.

Expected value =

The fixed cοst οf cοnducting the fοur prοmοtiοns is estimated tο be 16000 dοllars with a variable cοst οf 4 dοllars per custοmer fοr mailing and handling cοsts. What is the minimum number οf custοmers required by the cοmpany in οrder tο cοver the cοst οf prοmοtiοns? (Rοund yοur answer up tο the next highest integer.)

Break even pοint =

The interest Kevin earns in the first year that is $105 that will also earn interest in subsequent years. This is called compound interest.

Percent is a way of expressing a number as a fraction of 100, often used to represent a proportion or rate. It is denoted by the symbol "%". For example, if 30 out of 100 students in a class got an "A" grade, then the percentage of students who got an "A" grade is 30%.

Here,

Kevin deposits $100 into a savings account today. This is his principal. In one year, Kevin’s money earns 5 percent. The $5 he earns is his interest. In one year’s time, Kevin’s money is worth $105. This is his balance.

To find the interest earned in one year, we need to multiply the initial deposit by the interest rate (as a decimal). So:

Interest earned in one year = $100 x 0.05 = $5

To find the total value of Kevin's savings account after one year, we need to add the interest earned to the initial deposit. So:

Total value after one year = $100 + $5 = $105

To know more about percent,

https://brainly.com/question/29172752

#SPJ1

If the middle point of two points A(-2, 5) and B(-5, y) is (2−7​,3), then the distance between points A and B is 10.67 (rounded to two decimal places).

If the middle point of two points A(-2, 5) and B(-5, y) is (2−7​,3), then we have two unknowns. We will have to use the distance formula to solve the question. Distance Formula: The distance formula is a formula that is used to calculate the distance between two points in a plane. The formula is given as follows: d = √[(x₂ - x₁)² + (y₂ - y₁)²]

Now let's find the missing coordinate value. We will substitute the coordinates of point B in the equation as follows:(-2-5)/2 = -3.5y = -6 - 7 = -13

Now we can find the distance between points A and B by substituting their respective coordinates in the distance formula:d = √[(-5 - (-2))² + (-13 - 5)²]d = √[(-3)² + (-18)²]d = √(9 + 324)d = √333d = 10.67

Therefore, the distance between points A and B is 10.67 (rounded to two decimal places).

You can learn more about the middle point at: brainly.com/question/24111285

#SPJ11

By factorial, 6 is different ways can they stand in line.

What does the arithmetic term factorial mean?

Factorial is a mathematical term that refers to the sum of all positive integers that are less than or equal to a particular positive integer and are symbolized by that positive integer plus an exclamation point.

                           As a result, factorial seven is denoted by the symbol 7!, which stands for 1 2 3 4 5 6 7. Factorial zero is equivalent to one.

Three students, Nicole, Xavier, and Avani  line up one behind the other.

The different ways they can stand in line = 3!

       = 3 * 2 * 1

        = 6

Learn more about factorial

brainly.com/question/15689921

#SPJ1

The volume of the tin in cubic meter is equal to 785 cubic meter.

Mathematically, the volume of a cylinder can be calculated by using this formula:

Volume of a cylinder, V = πr²h

Where:

Assuming the radius of the base is 5 cm and the height of this tin is 10 cm, the volume of the tin in cubic meter can be calculated as follows;

Volume of a cylinder, V = 3.14 × 5² × 10

Volume of a cylinder, V = 3.14 × 250

Volume of a cylinder, V = 785 cubic meter.

Read more on cylinder here: brainly.com/question/14060443

#SPJ1

Answer: To calculate the probability of an incorrect test result, we need to consider two cases:

1. The test gives a positive result when the child does not have a pet allergy (false positive).

2. The test gives a negative result when the child does have a pet allergy (false negative).

The probability of a false positive is given as 0.06, which means that out of 100 children who do not have a pet allergy, 6 will test positive for it. The probability of a false negative is given as 0.12, which means that out of 100 children who do have a pet allergy, 12 will test negative for it.

To calculate the probability of an incorrect test result, we can add the probabilities of these two cases:

Probability of incorrect test result = Probability of false positive + Probability of false negative

Probability of incorrect test result = 0.06 + 0.12

Probability of incorrect test result = 0.18

Therefore, the probability of an incorrect test result is 0.18, or 18% (rounded to two decimal places).

Answer: 9 men will build the same wall in 25 hours.

Step-by-step explanation: 1 man will build the same wall in (45*5) hours

9 men will build the same wall in (45*5)/9 =25 hours

The given story has a sampling type known as: voluntary response sampling.

Voluntary response sampling: This is similar to a convenience sample but a voluntary response sample is mainly based on ease of access. Instead of the researcher choosing participants and directly contacting them, people volunteer themselves (e.g. by responding to a public online survey).

For example, a person being called in a radio show poll might have powerful opinions over a topic in any direction. In a voluntary random sample, chooses themselves by answering a common appeal.  These samples are unreliable because they are bias, hence the result is usually biased.

In this question, Mrs. Finn is dissatisfied with the hotel and voluntarily gives a response based on her experience and as such it fits with the definition of voluntary response sampling.

Read more about voluntary sampling at: https://brainly.com/question/13298621

#SPJ1

Answer:

7.16  (in meters)

Step-by-step explanation:

Notice the drawing.
The total height from the ground is given by h+1.5

To find h you need to use the right triangle, since you need the opposite side,

[tex]h=7sin(54)[/tex]

so total height is
[tex]H=1.5+7sin(54)[/tex]

be carefull your calculator is set to DEGREES

the answer is:

H = 7.16m rounded to nearest hundredth

The equation that represents Mr. Jarod's earnings for the job is option 3: m = 15h.

The problem states that Mr. Jarod's earnings vary directly with the number of haircuts he gives. This means that as the number of haircuts increases, his earnings also increase by a constant factor. We can represent this relationship using a proportionality constant, k.

m ∝ h

We can rewrite this proportionality using an equation:

m = kh

We can find the value of k by using the given information that Mr. Jarod earns $15 for five haircuts.

15 = k(5)

k = 3

Now we can substitute this value of k in the equation:

m = 3h

However, this is not the answer we are looking for. We want an equation that represents Mr. Jarod's earnings in terms of the number of haircuts, h. We can rearrange the equation to solve for m:

m = kh = 3h

Therefore, the equation that represents Mr. Jarod's earnings for the job is option 3: m = 15h.-

Learn more about Equations:

https://brainly.com/question/22688504

#SPJ4

The total number of pets is = 36.

This problem is incomplete, we do not know the fraction of the students that have a dog and also have a cat. Suppose we write the problem as:

"In Mrs.Hu's classroom, 4/5 of the students have a dog as a pet. X of the students who have a dog as a pet also have cat as a pet. If there are 45 students in her class, how many have both a dog and a cat as pets?"

Where X must be a positive number smaller than one, now we can solve it:

we know that in the class we have 45 students, and 4/5 of those students have dogs, so the number of students that have a dog as a pet is:

N = 45*(4/5) = 36

And we know that X of those 36 students also have a cat, so the number of students that have a dog and a cat is:

M = 36*X

now, we do not have, suppose that the value of X is 1/2 ("1/2 of the students who have a dog also have a cat")

M = 36*(1/2) = 18

So you can replace the value of X in the equation and find the number of students that have a dog and a cat as pets.

The total number of pets is = 36.

The complete question is-

In Mrs.Hu's classroom, 4/5 of the students have a dog as a pet. Of the students who have a dog as a pet also have a cat as a pet. If there are 45 students in her class, how many have both a dog and a cat as pets?

learn more about fractions,

https://brainly.com/question/10354322

#SPJ4

The predicted number of chirps per second when the temperature is 55 degrees Fahrenheit is 190.

The temperature and the number of chirps per second are linearly related, as shown by the trend line equation y = 3x + 25, where x is the temperature in degrees Fahrenheit and y is the number of chirps per second.

We must enter x = 55 into the equation and find y in order to estimate the number of chirps per second at a temperature of 55 degrees Fahrenheit

y = 3x + 25

y = 3(55) + 25

y = 165 + 25

y = 190

190 chirps are therefore expected per second at a temperature of 55 degrees Fahrenheit. Therefore, the predicted number of chirps per second when the temperature is 55 degrees Fahrenheit is 190.

Learn more about Fahrenheit here:

https://brainly.com/question/30719934

#SPJ4

sin(θ + φ) = 4/5.Using the sum identity for sine, we can find sin(θ + φ) in terms of sinθ, sinφ, cosθ, and cosφ:

sin(θ + φ) = sinθ cosφ + cosθ sinφ

We are given that sinθ = -3/5 and θ terminates in Quadrant III, which means that cosine is negative. Using the Pythagorean identity, we can solve for cosθ:

cosθ = √(1 - sin²(θ))

= -√(1 - (-3/5)²)

= -4/5

We are also given that tanφ = -7/24 and φ terminates in Quadrant II, which means that sine is positive and cosine is negative. Using the Pythagorean identity, we can solve for sinφ and cosφ:

tanφ = sinφ/cosφ = -7/24

sinφ = -7/√(7² + 24²) = -7/25

cosφ = -24/√(7² + 24²) = -24/25

Now we can substitute the values of sinθ, sinφ, cosθ, and cosφ into the formula for sin(θ + φ):

sin(θ + φ) = sinθ cosφ + cosθ sinφ

= (-3/5)(-24/25) + (-4/5)(-7/25)

= 72/125 + 28/125

= 100/125

= 4/5

Therefore, sin(θ + φ) = 4/5.

In LaTeX form, the equation for sin(θ + φ) is:

sin(θ + φ) = sinθ cosφ + cosθ sinφ

where sinθ  = -3/5, cosθ = -4/5, sinφ = -7/25, and cosφ = -24/25.

Find out more about Quadrant

brainly.com/question/26123150

#SPJ4

the perimeter of the regular hexagon is 48 cm.

A regular hexagon is a polygon with six sides, and each side has the same length. The formula to calculate the perimeter of a regular hexagon is given as:

Perimeter = 6 × length of one side

To find the length of one side of the hexagon, we need to use the given information about the area. The formula for the area of a regular hexagon is given as:

Area = (3 × √3 × s^2)/2, where s is the length of one side of the hexagon.

We can use this formula to solve for the length of one side:

96 √3 = (3 × √3 × s^2)/2

Simplifying this equation, we get:

s^2 = (2 × 96 √3)/(3 × √3)

s^2 = 64

s = 8 cm

Now that we know the length of one side of the hexagon, we can use the formula for perimeter to find the total perimeter:

Perimeter = 6 × 8 cm

Perimeter = 48 cm

Therefore, the perimeter of the regular hexagon is 48 cm.

In a regular hexagon, all six angles are equal, each measuring 120 degrees. It is a symmetrical shape, meaning that it has six lines of symmetry. The regular hexagon is a common shape in nature and architecture, and it is often used in geometry problems because of its regularity and symmetry. The hexagon is also the basis for the hexagonal lattice structure, which is a common pattern in crystals and other materials.

To know more about perimeter of the regular hexagon click here:

brainly.com/question/14338151

#SPJ4

There are 40,320 different orders of finish for the 8 teams in 5A West Conference.

The number of different orders of finish for the 8 teams in 5A West Conference can be calculated using the formula for permutations. The formula for permutations is n!/(n-r)! where n is the total number of items and r is the number of items being arranged.For this problem, there are 8 teams and all of them must be arranged in a specific order. Therefore, we need to calculate the permutation of all 8 teams.Using the permutation formula, we have:n!/(n-r)! = 8!/(8-8)! = 8!/(0!) = 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 40,320

Therefore, there are 40,320 different orders of finish for the 8 teams in 5A West Conference.

Learn more about West Conference

brainly.com/question/28387089

#SPJ4

Answer:

7.72

Step-by-step explanation:

Answer:

Step-by-step explanation:

in the number line it shows 7.7 ,7.8 and 7.9

that just mean it's 7.71

so the answer is 7.72

therefore A=7.72

The height of the tree is 8.84 m, rounded to the nearest hundredth.

Julia can use the ratio of the length of the shadows of the two objects (herself and the tree) to determine the height of the tree. To do this, first measure the length of her shadow and the length of the tree's shadow, which are 1.60 m and 32.84 m respectively.
Next, she needs to measure the distance from the base of the tree along the tree's shadow to the point where her shadow exactly overlaps the end of the tree top's shadow. In this case, it is 22.78 m.

Finally, she needs to use the following formula:
Height of tree = (Length of tree shadow x Height of person)/Length of person's shadow
Plugging in the values, we get:
Height of tree = (32.84 m x 1.60 m) / 22.78 m = 8.84 m

for such more questions on trignometry

https://brainly.com/question/13729598

#SPJ11

The length οf the parallelοgram is 6.15 cm.

The whοle length οf a shape's bοundary is referred tο in geοmetry as the perimeter οf the shape.

Adding the lengths οf all the sides and edges that surrοund a fοrm yields its perimeter. It is calculated using linear length units such centimetres, metres, inches, and feet.

Here the given Perimeter οf parallelοgram = 20.5 cm.

Side  = 4.1 cm

Nοw perimeter οf parallelοgram = 2(a+b) unit

=> 20.5 = 2(a+4.1)

=> a+4.1 = 10.25

=> a = 10.25-4.1 = 6.15 cm.

Hence the length οf the parallelοgram is 6.15 cm.

To learn more about perimeter refer the below link

https://brainly.com/question/19819849

#SPJ1

The function which represents the inverse of the function f(x)=[tex]x^2[/tex]+5 is [tex]f^{(-1)(x)}[/tex] = ±[tex]\sqrt{(x - 5)}[/tex].

To find the inverse of a function, we can follow the steps:

Step 1: Replace f(x) with y. So we have:

y = [tex]x^2[/tex] + 5

Step 2: Swap x and y in the equation obtained in step 1:

x = [tex]y^2[/tex] + 5

Step 3: Solve for y in the equation obtained in step 2:

x - 5 = [tex]y^2[/tex]

y = ±[tex]\sqrt{(x - 5)}[/tex]

Note that we need to include both the positive and negative square roots to get the complete inverse function. Therefore, the inverse function of f(x) = [tex]x^2[/tex] + 5 is:

[tex]f^{(-1)(x)}[/tex] = ±[tex]\sqrt{(x - 5)}[/tex]

To learn more about function, refer:-

https://brainly.com/question/30721594

#SPJ4

x for which f′(x) = 0 is 2.75.

Given f(x) = (4x - 3)(2x - 5)a. To determine the value of f(1)Substitute x = 1 in the given function.f(x) = (4x - 3)(2x - 5)f(1) = (4(1) - 3)(2(1) - 5)f(1) = (4 - 3)(2 - 5)f(1) = (1)(-3)f(1) = -3Therefore, the value of f(1) is -3.b. To determine the value of f′(1)We know that f'(x) = (d/dx) [(4x - 3)(2x - 5)]Differentiating the given function, we get f'(x) = 8x - 22Therefore, f′(1) = 8(1) - 22f′(1) = -14Therefore, the value of f′(1) is -14.c. To determine the value of f′′(1)Differentiating the above function again, we getf''(x) = d/dx(8x - 22)f''(x) = 8Therefore, f′′(1) = 8Therefore, the value of f′′(1) is 8.d. To determine the values of x for which f(x) = 0Substitute f(x) = 0, we get(4x - 3)(2x - 5) = 0Either 4x - 3 = 0 or 2x - 5 = 0x = 3/4 or x = 5/2Therefore, the values of x for which f(x) = 0 are 3/4 and 5/2.e. To determine the values of x for which f′(x) = 0We know that f'(x) = 8x - 22For f'(x) to be 0, 8x - 22 = 0 or 8x = 22x = 22/8 = 2.75Therefore, the value of x for which f′(x) = 0 is 2.75.

Learn more about Function

brainly.com/question/12431044

#SPJ4

Answer:

Step-by-step explanation:

a= first form a equation

lets call the cheese c and the buns b

2c+3b=10

c=2+b

3c+4b=12

now its a simultaneous equation

2c+3b=10    x3

3c+4b=12    x2

6c+9b=30

6c+8b=24

1b=6

b=6

now substitute it in to 2c+3b=10

2c+18=10

2c+-8

so c=$4

b= 56 difference 14

56/2=28

28-7

21

28+7=35

so the 2 numbers are 21 and 35

The solid curve shows that the points on the curve are part of the inequality solution set, and the shade inside the parabola indicates that the points below the curve are part of the solution set as well.

In mathematics, an inequality is a connection that is not equal between two expressions or values. Consequently, imbalance leads to inequity. In mathematics, an inequality connects two unrelated values. Inequality is separate from equality. When two values are not equal, the not equal sign is most usually used (). Various inequalities are employed to contrast values, no matter how little or huge. Many basic inequalities may be solved by altering the two sides until the variables are all that remain. Yet, a variety of factors contribute to inequality: Negative values on both sides are split or added. Trade off the left and right.

The upward opening parabola constructed with a solid curve, vertex at (0, 2), and shading inside the parabola indicates the solution of y x2 + 2. This is due to the fact that the inequality y x2 + 2 reflects all of the points (x, y) that are either on or below the curve y = x2 + 2. The solid curve shows that the points on the curve are part of the solution set, and the shade inside the parabola indicates that the points below the curve are part of the solution set as well.

To know more about inequality visit:

https://brainly.com/question/29914203

#SPJ1

Solution for the variable 'y' is y = (x - x² + 8)/5  

To solve the following equation we need to isolate the variable 'y' this can be done by adding or subtracting the same integer on both sides

Similarly, multiply or divide with the same integer on both sides. Note that these adding subtractions, multiplying, or dividing don't change the condition of the equation.

Here we have

5y+x² = x+8  

To solve the above equation we need to isolate 'y' as follows

=> 5y+x² = x+8    

Subtract x² from both sides

=> 5y + x² - x² = x + 8

=> 5y = x - x²+ 8

Divide by '5' on both sides

=> 5y/5 = (x - x² + 8)/5

=> y = (x - x² + 8)/5  

Therefore,

Solution for the variable 'y' is y = (x - x² + 8)/5  

Learn more about Equations at

https://brainly.com/question/24049564

#SPJ1

Solve for 'y', 5y+x² = x+8    

Hence, in answering the stated question, we may say that 128.57 quadrilateral degrees is the angle C. D is equal to 171.42 degrees.

A quadrilateral in geometry is a four-sided polygon with outer walls and four corners. The term comes from the Roman terms quadri and lead people to make bad (meaning "side"). A rectangle is a two-dimensional shape with sidewalls, four vertices, and four corners. Concave and convex surfaces are usually divided into two types. Trapezoids, parallelograms, rectangular, rhombuses, and squares are also subclasses of convex quadrilaterals. A rectangle is an a double form that has four straight sides. Parallelograms, trapezoids, triangles, kites, squares, etc rhombuses are examples of quadrilaterals.

The total of a quadrilateral's internal angles equals 360 degrees.

The four inner angles of the quadrilateral ABCD are denoted as follows:

A-angle = 3x

B angle = 4x

Angle C = 5(3x) = 15x (since it is 5 times angle A)

Angle D = 5(4x) = 20x (since angle B is five times larger).

3x + 4x + 15x + 20x = 42x is the sum of these four angles.

3x + 4x + 15x + 20x = 360

42x = 360

x = 8.57 (rounded to two places) (rounded to two places)

Angle A = 3x + 3(8.57) = 25.71°

Angle B = 4x + 4(8.57) = 34.28°

Angle C = 15x + 15(8.57) = 128.57

D = 20x = 20(8.57) = 171.42 degree angle

As a result, the quadrilateral's internal angles are:

A angle of 25.71 degrees

34.28 degrees is the angle B.

128.57 degrees is the angle C.

D is equal to 171.42 degrees.

To know more about quadrilateral visit:

https://brainly.com/question/29934291

#SPJ1