math help???

Question

about how much edging would be required to enclose a circular garden whose area is 75 square feet?

Answer 1

Edging is perimeter. This is 2∏r with r being the radius of the circular garden. So we want to figure out what r is.

They give you the area of the garden. Area is ∏r² = 75 sq ft
∏r² = 75 sq ft

Solve for r
r² = 75/∏
r = √(75/∏)

So the edging required is 2∏r = 2∏ √(75/∏)
Use your calculator now and get that the perimeter (amount of edging) needed is, which is ~31 feet.

Answer 2

You know the area, you need the edge, which means the circumference or perimeter of the circle.

Area formula is:

A = pi(r^2)

75 = pi(r^2)

Solve for r^2 by dividing each side by pi (3.14) and then take the square root of both sides.

75/pi = r^2

4.89 = r

Next, use the formula for circumference: C = 2rpi

C = 2(4.89) (3.14)

C = 30.71 would be the edge required to enclose the circular garden.

NOTE: 30.71 feet is ABOUT 31 feet when rounded off to the nearest unit or ones place. Is this clear?

Guido

Answer 3

This is obviously a circular garden. The area of a circle is given by the formula

A = pi(r^2). But A = 75, so

75 = pi(r^2), and

(75/pi) = r^2, meaning

r = sqrt (75/pi) = sqrt(75) / sqrt(pi) = 5sqrt(3) / sqrt(pi)

The circumference is what we are looking for to determine the edging. Remember that the circumference of a circle is equal to
C = 2pi(r), so

C = 2pi (5sqrt(3) / sqrt(pi))

This simplifies into

C = 10 sqrt(3pi)

I'll leave the "in between" steps for you to solve.

Answer 4

First find the radius of the garden from the Area given using the formula for the area of a circle. A = pi*r^2. Then find the circumference from the radius using C = pi*2*r.

Answer 5

A=75ft^2=πr^2
r^2=75/π=23.87ft^2
r=4.89ft
c=2πr=30.7 ft

Answer 6

Area of a circle is pi*r^2 where r = radius

The circumference of that circle is 2*pi*r

if pi*r^2 = 75, then r = sqrt(75/pi)

So the circumference is 2 * pi * r
= 2 * pi * (sqrt(75/pi))

(or about 30.70 feet).

Answer 7

A=πr^2
Here,
75 = πr^2
r^2=75/π=23.87
r= SQRT (23.87) = 4.89ft

c=2πr=30.7 ft

Answer 8

r=sqrt(A/pi)

C=2pi(r) 2(pi)sqrt(75/pi)

little more than 30 feet.

Answer 9

area=pir^2
75=22/7*r*r
(75*7)/22=r*r
525/22=r*r
23.86=r*r
r=4.89
c=2pir
2*(22/7)*4.89
9.78*(22/7)=30.7