Question

The area of circle B is 144 pi ft². Find the circumference of circle B.

Answer 1

Data:
$A_{cB} = 144 \pi ft^2$
Circumference length = ?

Note¹: Knowing that the area of ​​the circle "B" is calculated by the following formula: $A_{cB} = \pi *r^2$, using the data we have will find the value of the radius.

Data: $A_{cB} = 144 \pi ft^2$

Solving:
$A_{cB} = \pi *r^2$
$144 \pi = \pi *r^2$
$\pi *r^2 = 144 \pi$
$r^2 = \frac{144 \diagup\!\!\!\!\!\pi }{ \diagup\!\!\!\!\!\pi }$
$r = \sqrt{144}$
$\boxed{r = 12\:ft}$

Note²: Now, we will find the size of the circumference with the data already collected, so we will have:

Formula: $C = 2* \pi *r$
Adopting: $\pi \approx 3.14$

Solving:
$C = 2* \pi *r$
$C = 2* 3.14 *12$
$\boxed{\boxed{C \approx 75.36\:ft}}\end{array}}\qquad\quad\checkmark$