Question

Jason designed an arch made of wrought iron for the top of a mall entrance. The 11 segments between the two concentric circles are each 1.25 m long. Find the total length of wrought iron used to make the structure. Round the answer to the nearest meter.

Answer 1

57 m

Explanation:

Answer 2

diameter of the bigger semi-circle is 15 m
circumference of the bigger semi-circle = πd = 15π

diameter of the smaller semi-circle = 15 - 2(1.25) = 15 - 2.5 = 12.5 m
circumference of the smaller semi-circle = πd = 12.5π m

Total length of the segments between the two circles = 11(1.25) = 13.75 m

Total length of wrought iron used = 15π + 12.5π + 13.75 = 100 m