Calculate Circle Radius: Converting 25 cm² Area Using A = πr²

Question

A circle has an area of 25 cm².

What is its radius?

00:00 Find the circle's radius

00:03 We'll use the formula for calculating circle area

00:14 We'll substitute the area value according to the given data and solve for the radius

00:20 We'll isolate the radius R

00:37 Make sure to take the square root of both numerator and denominator

00:48 And this is the solution to the question

Area of the circle:

$S=\pi r^2$

We insert the known data:

$25=\pi r^2$

Divide by Pi: $\frac{25}{\pi}=r^2$

Extract the root: $\sqrt{\frac{25}{\pi}}=r$

$\frac{5}{\sqrt{\pi}}=r$

$\frac{5}{\sqrt{\pi}}$ cm