Year 12/AS Pure Chapter 9.3 (Trigonometric Ratios)

This lesson looks at finding the areas of triangles. We start by remembering the 'basic' formula for working out the area of a triangle and then showing that this is actually a particular case of the general formula, A = (½)absinC. We then once again take a look at solving tricky multi-step problems.

Introduction: 00:00

Solution to Warm-Up Q1: 1:01
Solution to Warm-Up Q2: 4:56
Solution to Warm-Up Q3: 8:53
Solution to Warm-Up Q4: 12:21

Recap - formula for area of triangle: 13:39
Proof - area of triangle = (½)absinC: 15:14

FINDING AREAS OF TRIANGLES
Worked Example 1: 19:23
Worked Example 2: 21:16

SOLVING MULTI-STEP TRIANGLE PROBLEMS
Introduction and advice: 32:44
Student activity/worked example: 33:18

Suggested Exercises: 43:14

[MrBaileyMaths]

Timestamps for smartphones and tablets:

Introduction: 00:00

Solution to Warm-Up Q1: 1:01
Solution to Warm-Up Q2: 4:56
Solution to Warm-Up Q3: 8:53
Solution to Warm-Up Q4: 12:21

Recap - formula for area of triangle: 13:39
Proof - area of triangle = (½)absinC: 15:14

FINDING AREAS OF TRIANGLES
Worked Example 1: 19:23
Worked Example 2: 21:16

SOLVING MULTI-STEP TRIANGLE PROBLEMS
Introduction and advice: 32:44
Student activity/worked example: 33:18

Suggested Exercises: 43:14