How do i calulate the radis of a circle?

To calculate the radius of a circle, you can use the formula ( r = \frac{d}{2} ), where ( d ) is the diameter of the circle. If you have the circumference ( C ), you can find the radius using the formula ( r = \frac{C}{2\pi} ). Additionally, if you know the area ( A ), you can calculate the radius with ( r = \sqrt{\frac{A}{\pi}} ).