There are many ways you can calculate the length of a radius of a circle. Let's start with the obvious.
A radius is half the length of a diameter. So if you have the length of a diameter, just divide in half and there's your radius!
If you only have the circumference of a circle, you can use the formula
r = C ÷ (2[tex] \pi [/tex])
C being the circumference.
Hope this helped!
