measure of lengths of segments and arcs

what is the diameter of a circle if its area is 100pi cm^2 ?

solution

First,write the formula,

A=r^2 pi

now, substitute in what you know.

100 pi=r^2 pi

by dividing both sides of equation by pi

100=r^2

then,take the square root of both sides

10=r

Remember that you are solving for diameter

d=2r

d=2×10

d=20

the answer is the diameter , d= 20

The area of circle is 25 pi . what is the radius?

first write the formula , A=pi r^2

substitute in what you know.

25pi = r^2pi

by dividing both sides of the eq. by pi

25=r^2

take the square root of both sides

5=r

the answer is r=5 .

total contributions (2)

what is the diameter of a circle if its area is 100pi cm^2 ?

solution

First,write the formula,

A=r^2 pi

now, substitute in what you know.

100 pi=r^2 pi

by dividing both sides of equation by pi

100=r^2

then,take the square root of both sides

10=r

Remember that you are solving for diameter

d=2r

d=2×10

d=20

the answer is the diameter , d= 20