MA30-04 Maths Coming soon

Angles of elevation and depression

MA30-04

This lesson is coming soon.

Watch now instead: MA32-01 Mean, median, mode and range

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

angle of elevation angle of depression horizontal

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.