Question

suppose that we are standing on a bridge 30 feet above a river watching a log floating toward we. if the angle with horizontal to the front of the log is 16.7degree and angle with horizontal to the back of the log is 14degree, how long is the log?

Answer 1

If the front of the log is at distance d, and the log has length x, then

30/d = tan 16.7°
30/(d+x) = tan 14°

eliminate d and we have

30/tan16.7° = 30/tan14° - x

now just solve for x, the length of the log.

Answer 2

-0.06