In this formula, A is the area of the circle. The image below shows what we mean by finding the radius from the area:
How to Find the Radius from the Area
Finding the radius from the area is easy.Question
What is the radius of the circle, with area 10 cm2, below?
Step-by-Step:
1
Start with the formula:
Radius = √ (A⁄π)
Don't forget: √ means square root, / means ÷ and π is pi (≈ 3.14)
2
Substitute the area into the formula. In our example, A = 10.
Radius = √ (10⁄π)
Radius = √ (10 ÷ π)
Radius = √ (10 ÷ 3.14)
Radius = √ 3.18
Radius = 1.78 cm
Answer:
The radius of the circle is 1.78 cm.Interactive Widget
Here is an interactive widget to help you learn about finding the radius of a circle from its area.
This page was written by Stephen Clarke.
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