Problema Solution

A forest ranger is watching the progress of a forest fire spreading towards her from the top of a 3785-foot mesa. In 4 minutes, the angle of depression to the leading edge of the fire changes from 10.8 degrees to 12.59 degrees.

How many feet does the fire advance during the 4 minutes that the ranger is observing it?

Answer provided by our tutors

make a good drawing and use trigonometry


let 'd' represent the distance that the fire advance during the 4 minutes


d = 3785/(tan(10.8)) - 3785/(tan(12.59))


calculating we find:


d = 2,894.65 ft


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during the 4 minutes the fire will advance by 2,894.65 feet.