C.) If the area of a circle is 121 square units, what is its diameter?

12.41

Step-by-step

A

=

π

*

r

2

If you know the area, then you can find the radius:

Divide the area by

π

, then find the square root.

r

=

√

A

π

→

r

=

√

121

π

π

=

√

121

=

11

units

Once you know the radius, you can find the circumference:

C

=

2

*

π

*

r

=

2

*

3.14

*

11

C

=

69.08

≈

69.1

units