Year 11 - Maths
The sine rule
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 derive and use the formula for the sine rule.
Key Notes
- The sides of a triangle are proportional to the sines of their opposite angles
- A diagram can aid with understanding this
- The sine rule is useful when you know an angle and side pair and wish to find another pair
- In order to do this, you will need either a side length or an angle
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.
Common Mistakes To Avoid
- Pupils may be uncertain about which angle pairs with which side.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The sides of a triangle are proportional to the sines of their opposite angles. A diagram can aid with understanding this.
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 about which angle pairs with which side. Correction: The angle is paired with the side length that is opposite.
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
- Using the sine and cosine rules Study Guide
Browse all guides in the Year 11 Maths guide library.