Question

Given the width of the lawnmower is 2.2 feet and the length of the rope is 22 feet calculate the radius of the pole that will produce a perfect lawn

Answer 1

0.35 ft

Explanation:

We assume that the lawnmower is mowing a spiral around the pole and that each turn increases the radius by 2.2 feet. That is, each turn around the pole captures (or releases) 2.2 feet of rope, so that is the circumference of the pole.

C = 2πr

2.2 ft = 2(22/7) r

(2.2 ft)(7/44) = r = 0.35 ft

The radius of the pole needs to be about 0.35 feet, or 4.2 inches.

_____

We assume that the lawnmower width is a multiple of 22 because we are intended to use 22/7 as our approximation of pi. A more accurate value of pi would give a radius of 0.35014 feet, about 4.202 inches.