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

User Plpicard
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2 Answers

5 votes

Answer:

a. 18 cm

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

User Daniel De Freitas
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5.2k points
6 votes

Answer:

a. 18 cm

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

User Piyush Zalani
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5.0k points