Jenny is 5 feet 2 inches tall. She casts a shadow of 7 feet 9 inches. There is a pole with a shadow of 15.5 feet. Find the pole's height.

Question

Both triangles are right angles. Need to use ratios and similarities to solve.

Answer 1

We know the ratios of heights to shadow lengths are the same. Convert the measurements to inches.

5ft 2in=62 in, 7ft 9in=93in, 15.5ft=15ft 6in=186in.

x/186=62/93 where x is pole height. x/(2×93)=62/93, so x=2×62=124in=10ft 4in.