Applications of Trigonometric Functions

Question

A firefighter standing 28 feet from the base of a burning building extends a ladder to a second-floor window in order to rescue a person. Find the distance that the ladder must reach to the nearest tenth of a foot if the angle of elevation of the ladder is 15°.

The distance the ladder must reach is approximately  ??? ft. 

Answer 1

We need to draw a right triangle with base of 28 feet. The acute angle is 15 degrees. The length that ladder must reach is the hypotenuse of the triangle. Since base and hypotenuse are involved, we need a cosine function

Cos (15 degree) = base/hypotenuse

Cos (15) = 28/H

0.966 = 28/H

or H the length of ladder is 28/0.966 = 28.99 feet