Question

the area of a circle is $81\pi$ square meters. what is the radius?
$a = 81\pi\\ m^2$
give the exact answer in simplest form.
meters

Explanation:

Step1: Recall circle area formula

$A = \pi r^2$

Step2: Substitute given area value

$81\pi = \pi r^2$

Step3: Cancel $\pi$ from both sides

$81 = r^2$

Step4: Solve for radius $r$

$r = \sqrt{81} = 9$

Answer:

9 meters