Question

Carlos is spreading mulch in a circle on top of an area where he has planted some seeds. He has enough mulch to cover an area that is 12.5 square feet. How much rubber edging does Carlos need to encircle the mulch that will cover the seeds?

Answer 1

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.