## SIMILARITY & TRIGONOMETRY

## OVERVIEW

Trigonometry is introduced as a special case of similarity within right-angled

triangles linking to the introductory lesson in Year 9. Emphasis is placed throughout the steps on linking the trig functions to ratios, rather than just functions.

This key topic is introduced early in Year 10 to allow regular revisiting e.g. when looking at bearings.

There is sufficient time for Foundation classes to revise Pythagoras Theorem in depth.

## Lesson Resources

Lesson 1 – Enlargement positive scale factors

Lesson 2 – Enlarging from a point

Lesson 3 – Enlargement fractional scale factors

Lesson 4 – Enlargement negative scale factors (Higher only)

Lesson 5– Similar Shapes

Lesson 6 – Similar Triangles and Parallel Lines (Higher only)

Lesson 7 – Similar Area (Higher only)

Lesson 8 – Similar Volume (Higher only)

Lesson 9 – The Sine Ratio

Lesson 10 – Using all three ratios to find missing lengths

Lesson 11 – Using all three ratios to find missing angles

Lesson 12 – Working with exact values

Lesson 13 – Pythagoras or Trigonometry?

Lesson 14 – Solving area problems with Trigonometry

Lesson 15 – The Sine Rule (Higher only)

Lesson 16 – The Cosine Rule (Higher only)

Lesson 17 – Sine or Cosine Rule? (Higher only)

Lesson 18 – Bearings and Trigonometry (Higher only)

Lesson 19 – Area of non-right angled triangles (Higher only)

The previous Trigonometry lessons can be found here