Question

A circle has an area of 324π cm2. What is the radius? a. 18 cm c. 18π cm b. 36π cm d. 36 cm

Answer 1

Answer:

a. 18 cm

Step-by-step explanation:

We are given that a circle has an area of 324π cm2. We are required to determine its radius. The formula for the area of a circle with radius r units is;

$A=pi*r*r$

We plug in the area given and solve for r;

$324pi=pi*r^{2}\\\\r^{2}=324\\\\r=18$

The radius of the circle is 18 cm

Answer 2

Answer:

a. 18 cm

Step-by-step explanation:

Area of a circle is given by: A=πr²

where r is the radius and A the area.

therefore we substitute A with the value for the area in the question.

324π=πr²

cancelling the factor π on both sides gives: 324=r²

√324=r

r=18cm