**10.1 Angle of Elevation and Angle of Depression**

**1.**

**Angle of elevation**is the acute angle measured from a

**horizontal line up**to the

**line of sight**.

**Example 1:**

Angle of elevation of object

*O*from*P*= ∠OPA**2. Angle of depression**is the acute angle measured

**down**from a

**horizontal line**to the

**line of sight**.

**Example 2:**

Angle of depression of object

*O*from*P*= ∠OPA**3.**The

**angle of elevation**or

**angle of depression**is always measured from the

**horizontal line.**

**Example 3:**

Diagram below shows two vertical poles

*JK*and*NL*on a horizontal plane.*M*is a point on*NL*such that*JK*=*ML*.The angle of depression of point

*J*from point*N*is

*Solution:*The angle of depression of point

*J*from*N*is the angle between line*JN*and the horizontal line through*N*.Angle of depression of

*J*from*N*= angle of elevation of

=∠NJM

*N*from*J*=∠NJM