Year 11 - Maths
Using the sine and cosine rules
Non right-angled trigonometry
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Study Guides
This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit, pupils explore how to apply knowledge in trigonometry to non right-angled triangles.
Lesson Summary
You will learn to use the formula for the cosine rule and the sine rule.
Key Notes
- The cosine rule is useful when you know three sides and an angle are involved
- The sine rule is useful when you know two pairs of sides and angles are involved
Vocabulary To Learn
- Sine rule: The sine rule is a formula used for calculating either an unknown side length or the size of an unknown angle.
- Cosine rule: The cosine rule is a formula used for calculating either an unknown side length or the size of an unknown angle.
Common Mistakes To Avoid
- Pupils may be uncertain over how to start a problem.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The cosine rule is useful when you know three sides and an angle are involved. The sine rule is useful when you know two pairs of sides and angles are involved.
2. Use this key word in a maths sentence and explain it clearly. 'Sine rule'
The sine rule is a formula used for calculating either an unknown side length or the size of an unknown angle. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may be uncertain over how to start a problem. Correction: Encourage pupils to draw a diagram if one is not provided and then to annotate the diagram with any given information as a first step. If a diagram is given then pupils should annotate that.
More Lessons In This Unit
- Calculating the area of any triangle when the height is not known Study Guide
- Checking and securing understanding of trigonometric ratios Study Guide
- Considering the appropriate trigonometric rule Study Guide
- Drawing the sine and cosine graphs Study Guide
- Drawing the tangent graph Study Guide
- Interpreting the trigonometric graphs Study Guide
- Problem solving with non right-angled trigonometry Study Guide
- The area of any triangle Study Guide
- The cosine rule Study Guide
- The sine rule Study Guide
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