Question

A person whose eye level is 15 feet above the ground is looking at a building. The angle of elevation to the top of the building is 40° and the angle of depression to the bottom of the building is 15°. What is the height in feet of the building?

Answer 1

61.97 feets

Explanation:

Using trigonometry :

Horizontal distance between the person and building,

Let distance = d

Tan 15 = 15 / d

0.2679491 * d = 15

d = 15 / 0.2679491

d = 55.980781

To obtain the height, h :

tan 40 = (h-15)/d

d = 55.98

h-15 = 55.98 (tan 40°)

h - 15 = 55.98 * 0.8390996

h - 15 = 46.972797

h = 46.972797 + 15

h = 61.972797

h = 61.97 feets