MA30-04 Maths Coming soon
Angles of elevation and depression
MA30-04
This lesson is coming soon.
In this lesson
Define the angle of elevation and the angle of depression relative to the horizontal, and use one inside a right-angled-triangle trigonometry calculation.
What it covers
- Define angle of elevation as the angle above the horizontal, measured from an observer looking up at an object
- Define angle of depression as the angle below the horizontal, measured from an observer looking down at an object
- The alternate-angle fact: the angle of elevation from A to B equals the angle of depression from B to A, since the two horizontals are parallel
- Draw the correct diagram convention (a dashed horizontal line at the observer's eye level) before setting up any trigonometry
- One worked example using an angle of elevation, and one using an angle of depression, inside a right-angled-triangle trigonometry calculation
Key words
For: Edexcel IGCSE 4MA1, Cambridge IGCSE 0580
On the specification
| Board | Spec | Statement |
|---|---|---|
| Edexcel IGCSE 4MA1 | H4.8B | Understand and use angles of elevation and depression |
| Cambridge IGCSE 0580 | E6.2 | Know and use the sine, cosine and tangent ratios for acute angles in calculations involving sides and angles of a right-angled triangle. |
For teachers
This GCSE Maths lesson teaches angles of elevation and depression. By the end, students should be able to define the angle of elevation and the angle of depression relative to the horizontal, and use one inside a right-angled-triangle trigonometry calculation. It works through two worked examples and the mistakes examiners report.