We are working with a circle, which means that our rubber edging needs to be as long as the circumference of the circle. Circumference (C) is calculated by multiplying the diameter (d) times pi (Ď€). [C=dĎ€] And the diameter is simply the radius (r) multiplied by two. [d=2r] We can calculate the radius by dividing 12.5 by pi and then taking the square root of the quotient.[r=âš(12.5/Ď€)] In this case, the radius is equal to 1.99. We then double the radius and multiply by pi.[C=2(1.99)Ď€] When we do, we find that the circumference is 12.5. Therefore, Carlos will need to buy 12.5 feet of rubber edging.
