Angles of elevation and depression

Math

Definition

The angle of elevation is the angle measured upward from the horizontal to a line of sight to an object above. The angle of depression is measured downward from the horizontal to an object below. Both use right-triangle trigonometry to solve real-world problems.

Examples

  • A person standing 50 feet from a building looks up at a 60° angle of elevation — the building's height is 50·tan(60°) ≈ 86.6 feet
  • A pilot at 5000 feet altitude sees a runway at a 3° angle of depression and calculates the ground distance
Key Fact

Angle of elevation from point A = angle of depression from point B (alternate interior angles)

Related Terms

Soh-cah-toa Solving right triangles Sine cosine tangent Law of sines

Study This Concept

Practice angles of elevation and depression with free review games in these units:

Trigonometry Unit 2: Right Triangle Trigonometry