# TrigonometryAngle of elevation: Which expression represents the eagle's height above the ground? (answer involves tan)

#### pan90

##### New member
We know the answer, but don't know how it makes sense given trigonometric principles.

Borrowed from HiSet free practice test

#### Monoxdifly

##### Well-known member
Hint: Tan = height/base

#### HallsofIvy

##### Well-known member
MHB Math Helper
As monoxdifly said, "tangent" is "opposite side over near side". Looking at the right triangle in tne picture, the "opposite side" to the 20 degree angle has length "x" and the "near side" has length 25 feet. tan(20)= x/25 so x= 25 tan(20). But x is the height of the eagle above the person's eye level, not the height of the eagle above the ground. We have to add the 5 feet from the ground 5o the person's eye level.