The figure at the right shows three circular pipes all with 12inch diameters the have been strapped together by a metal band.What is the lenght of the band?
The band consists of three congruent segments with 2r each, and three congruent arcs with 120o each. So, the length of the band is
3[2r + (1/3)2pi r]
= 6r + 2pi*r
= 36 + 12pi inches, since r = 6 inches