You are asked to measure the height of an inside wall of a warehouse. No ladder tall enough to measure the height is available. You borrow a mirror from a salesclerk and place it on the floor. You then move away from the mirror until you can see the reflection of the top of the wall in it, as shown in the figure. 

(a) Explain why triangle HFM is similar to triangle TBM. (In the reflection of light the angle of incidence, ∡HMF, equals the angle of reflection, ∡TMB. Thus, ∡HMF = ∡TMB.)

(b) If your eyes are  ft above the floor and you are  ft from the mirror and the mirror is 20 ft from the wall, how high is the wall?

Transcribed Image Text:

T H F M В