Mathematics Advanced Year 11 - Module 2 - Lesson 4
Trigonometric Ratios
1. Key Ideas
Engineers designing bridges, pilots navigating flight paths, and architects planning roofs all rely on the same three ratios: sine, cosine, and tangent. In this lesson, you will learn how these ratios are defined from both right-angled triangles and the unit circle, and how to use them to solve real-world problems.
- The definitions of $\sin \theta$, $\cos \theta$, and $\tan \theta$
- How trig ratios connect angles to side lengths in right triangles
2. Success Criteria
By the end, you should be able to:
- The definitions of $\sin \theta$, $\cos \theta$, and $\tan \theta$
- The relationship $\tan \theta = \frac{\sin \theta}{\cos \theta}$
- The Pythagorean identity
3. Key Terms
4. Activity: Build the Lesson Map
Use the lesson to complete the table. Keep answers brief but specific.
| Prompt | Your answer |
|---|---|
| Main concept | |
| Important example | |
| Common mistake to avoid | |
| How this links to the next lesson |
5. Short Answer Questions
1. Explain this lesson goal in your own words: "The definitions of $\sin \theta$, $\cos \theta$, and $\tan \theta$". Use one specific example from the lesson.
2. Apply this idea to a new example: "The relationship $\tan \theta = \frac{\sin \theta}{\cos \theta}$". Show your reasoning clearly.
3. Analyse why this idea matters for understanding Trigonometric Ratios: "The Pythagorean identity".
6. Extend: Apply the Idea
A student gives a memorised answer about Trigonometric Ratios but does not use evidence or reasoning.
Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.
7. Multiple Choice
1. What is the best first step when answering a question about Trigonometric Ratios?
A. Identify the key concept being tested
B. Write every fact from memory
C. Ignore the command word
D. Skip examples and evidence
2. Which answer would show stronger understanding of Trigonometric Ratios?
A. An answer with accurate terms and reasoning
B. A copied definition only
C. A single-word response
D. An answer with no example
3. What should you do if a question asks you to explain?
A. Link the idea to a reason or cause
B. List unrelated facts
C. Only draw a diagram
D. Write the shortest possible answer
8. Success Criteria Proof
Finish with evidence that you can do each success criterion.