Finding Sides Using the Cosine Rule – Complete Lesson

This is a complete lesson on the cosine rule that looks at how to calculate unknown sides of triangles. The lesson is designed with the new GCSE specification in mind.

Lesson Objectives

  • To work out unknown sides using the cosine rule.
  • To use the cosine rule to solve problems.

Who is this Lesson For?

This pack is designed for GCSE higher tier students. It could also be used with high ability Key Stage 3 students.

What is Included?

Included in this download are the following:

  • Full lesson plan for the ‘Finding Sides Using the Cosine Rule’ lesson, including introduction, teaching content, individual activities, plenary and suggested support and extension activities
  • Pythagoras’ Theorem Introduction
  • Cosine Rule Demonstration Slide
  • Finding a Side Using the Cosine Rule Example
  • Mini-Plenary
  • Student Worksheet on Finding Sides Using the Cosine Rule
  • True or False Cards
  • Further Trigonometry Fact Sheet
  • Complete Solutions to all Questions

Lesson Progression

This is the fourth lesson in the Further Trigonometry unit of work (the unit is also available as a pack including homework activities and a unit assessment).

The other lessons in the unit are: