A homeowner is fencing in his triangular

9. April's test scores in physics are 78, 85,65, 82, 90, and 95. Find the mean

Mariulka [41]

Answer:

82.5

Step-by-step explanation:

the mean and standard deviation of the data is 82.5

4 0

3 years ago

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The height (in feet) of punted football is a function of the time the ball is in the air. The function is defined by h(t) = - 7t

Kamila [148]

Answer:

The height of the football after 4 seconds is 80 feet.

Step-by-step explanation:

You know that the height (in feet) of punted football is a function of the time the ball is in the air and it is defined by:

h(t) = -7*t²+48*t

To calculate the height of the ball after 4 seconds, you must replace the time t by the time of 4 seconds:

h(4) = -7*4²+48*4

Solving, you get:

h(4) = -7*16+48*4

h(4) = -112+192

h(4)= 80

The height of the football after 4 seconds is 80 feet.

8 0

3 years ago

This week, we are covering relationships that can be approximated by linear equations. For instance, y = 453x + 3768 represents

lana [24]

Answer:

See explanation below.

Step-by-step explanation:

We assume that the data is given by :

x: 30, 30, 30, 50, 50, 50, 70,70, 70,90,90,90

y: 38, 43, 29, 32, 26, 33, 19, 27, 23, 14, 19, 21.

Where X represent the cost for scholarships in thousands of dollars and y represent the cost of life for an academic semester (The data comes from the web)

We can find the least-squares line appropriate for this data.

For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

So we can find the sums like this:

$\sum_{i=1}^n x_i = 30+30+30+50+50+50+70+70+70+90+90+90=720$

$\sum_{i=1}^n y_i =38+43+29+32+26+33+19+27+23+14+19+21=324$

$\sum_{i=1}^n x^2_i =30^2+30^2+30^2+50^2+50^2+50^2+70^2+70^2+70^2+90^2+90^2+90^2=49200$

$\sum_{i=1}^n y^2_i =38^2+43^2+29^2+32^2+26^2+33^2+19^2+27^2+23^2+14^2+19^2+21^2=9540$

$\sum_{i=1}^n x_i y_i =30*38+30*43+30*29+50*32+50*26+50*33+70*19+70*27+70*23+90*14+90*19+90*21=17540$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=49200-\frac{720^2}{12}=6000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=17540-\frac{720*324}{12}{12}=-1900$

And the slope would be:

$m=-\frac{1900}{6000}=-0.317$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{720}{12}=60$

$\bar y= \frac{\sum y_i}{n}=\frac{324}{12}=27$

And we can find the intercept using this:

$b=\bar y -m \bar x=27-(-0.317*60)=46.02$

So the line would be given by:

$y=-0.317 x +46.02$

We have an inverse linear relationship since the slope is negative between the variables of interest.

8 0

4 years ago

Determine the center and radius of the following circle equation: x2 + y2 + 18x – 18y + 113 = 0

Soloha48 [4]

Answer:

radius 7

center (-9,9)

Step-by-step explanation:

answer in the photo

3 0

4 years ago

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(07.06 LC)

soldi70 [24.7K]

It has infinitely many solutions....because all real numbers satisfy the equation.

Good luck mate :P

8 0

4 years ago

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