7. After 8 months, Joellen has lost 75 pounds. This is a 30% decrease in her starting weight. Find

A school wishes to enclose its rectangular playground using 480 meters of fencing.

Harlamova29_29 [7]

Answer:

Part a) $A(x)=(-x^2+240x)\ m^2$

Part b) The side length x that give the maximum area is 120 meters

Part c) The maximum area is 14,400 square meters

Step-by-step explanation:

The picture of the question in the attached figure

Part a) Find a function that gives the area A(x) of the playground (in square meters) in terms of x

we know that

The perimeter of the rectangular playground is given by

$P=2(L+W)$

we have

$P=480\ m\\L=x\ m$

substitute

$480=2(x+W)$

solve for W

$240=x+W\\W=(240-x)\ m$

<u><em>Find the area of the rectangular playground</em></u>

The area is given by

$A=LW$

we have

$L=x\ m\\W=(240-x)\ m$

substitute

$A=x(240-x)\\A=-x^2+240x$

Convert to function notation

$A(x)=(-x^2+240x)\ m^2$

Part b) What side length x gives the maximum area that the playground can have?

we have

$A(x)=-x^2+240x$

This function represent a vertical parabola open downward (the leading coefficient is negative)

The vertex represent a maximum

The x-coordinate of the vertex represent the length that give the maximum area that the playground can have

Convert the quadratic equation into vertex form

$A(x)=-x^2+240x$

Factor -1

$A(x)=-(x^2-240x)$

Complete the square

$A(x)=-(x^2-240x+120^2)+120^2$

$A(x)=-(x^2-240x+14,400)+14,400$

$A(x)=-(x-120)^2+14,400$

The vertex is the point (120,14,400)

therefore

The side length x that give the maximum area is 120 meters

Part c) What is the maximum area that the playground can have?

we know that

The y-coordinate of the vertex represent the maximum area

The vertex is the point (120,14,400) -----> see part b)

therefore

The maximum area is 14,400 square meters

Verify

$x=120\ m$

$W=(240-120)=120\ m$

The playground is a square

$A=120^2=14,400\ m^2$

8 0

3 years ago

Apparently giving out free points is against the Community Guidelines so lets try this again! Hey How is everyone? Also here is

loris [4]

Answer:

42.5 and i'm pretty good

Step-by-step explanation:

how r u doing

90-5=B/2=x

4 0

2 years ago

Read 2 more answers

I need someone to help me do this, see attached documents for the questions

Brilliant_brown [7]

Answer:

<u><em>1.) 20.2</em></u>

Step-by-step explanation:

1.) You need to use the distance formula:

$d=\sqrt{(x_{2}-x_{1})^2+(y_{2}-y_{1})^2}$

Find the distance of A to B first:

$(-2,2)(3,2)\\\\\sqrt{(3+2)^2+(2-2)^2}\\\\\sqrt{(5)^2+(0)^2}\\\\\sqrt{25} =5$

B to C:

$(3,2)(-1,-5)\\\\\sqrt{(-1-3)^2+(-5-2)^2}\\\\\sqrt{(-4)^2+(-7)^2}\\\\\sqrt{16+49}\\\\\sqrt{65} =8.06=8.1$

C to A:

$(-1,-5)(-2,2)\\\\\sqrt{(-2+1)^2+(2+5)^2}\\\\\sqrt{(-1)^2+(7)^2}\\\\\sqrt{1+49}\\\\\sqrt{50}=7.07=7.1$

Add distances to find the perimeter:

$5+8.1+7.1=20.2$

2.) Part A:

You need to use the mid-point formula:

$midpoint=(\frac{x_{1}+x_{2}}{2} ,\frac{y_{1}+y_{2}}{2} )$

$(3,2)(7,11)\\\\(\frac{3+7}{2},\frac{2+11}{2})\\\\(\frac{10}{2},\frac{13}{2})\\\\m=( 5,6.5)$

Part B:

1. Use the slope-intercept formula:

$y=mx+b$

M as the slope, b the y-intercept.

Find the slope of the two points A and B using the slope formula:

$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}} =\frac{rise}{run}$

Insert slope as m into equation.

Take point A as coordinates $(x,y)$ and insert into the equation. Solve for the intercept, b:

$(y)=m(x)+b$

Insert the value of b into the equation.

2. Use the mid-point coordinate. Take the slope.

If you need to find the perpendicular bisector, you will take the negative reciprocal of the slope. Switch the sign and flip it. Ex:

$\frac{1}{2} =-\frac{2}{1}=-2\\$

Insert the new slope into the slope-intercept equation as m.

Take the mid-point coordinate as (x,y) and insert into the equation with the new points. Solve for b.

Insert the value of b.

4 0

3 years ago

Jamal has run 7 miles from point a to point b of a race. the entire race from point a to point c is 26 miles. how many

Anon25 [30]

The number of more miles he needs to run to complete the race is 19 miles.

<h3 /><h3>How to find distance in miles?</h3>

He has run 7 miles from point a to point b of a race.

The entire race from point a to point c is 26 miles.

Therefore, the number of more miles he needs to run to complete the race is as follows:

let

x = the more miles he needs to run

Hence,

x = 26 - 7

x = 19 miles

Therefore, he needs to run 19 more miles to complete the race.

learn more on distance(miles) here: brainly.com/question/9950097

#SPJ1

8 0

1 year ago

Need help anyone know the answer

VladimirAG [237]

Answer:

5 and 6

Step-by-step explanation:

5 and 6

5 0

3 years ago

Read 2 more answers