The equation C=2piR is the formula that relates the circumference of a circle to the radius. This gives us the ability to calculate pi if we physically measure a circles circumference and radius. Solve the equation for pi to get the formula you would use to perform the activity.
we have the equation

Solve for pi
That means -----> isolate the constant pi
step 1
Divide the equation by 2*r both sides

the number pi is equal to divide the circumference by two times the radius