Question

Henry knows that the circumference of a circle is 18mc006-1.jpg inches. What is the area of the circle?

Answer 1

The complete question is:
Henry knows that the circumference of a circle is 18π inches. What is the area of the circle?

Solution:
Circumference (C) of the circle can be written as:

$C=2 \pi r \\ \\ 18 \pi =2 \pi r \\ \\ r=9$

Using this value of radius, we can find the Area(A) of the circle.

$A= \pi r^{2} \\ \\ A= \pi (9)^{2} \\ \\ A=81 \pi$

Therefore, area of the circle having a circumference of 18π inches will be 81π inches²