Students learn about calculating the hypotenuse in a right-angled triangle using Pythagoras' Theorem. Using Pythagorean Triples students calculate the area of the square attached to each edge of a triangle to discover the relationship between the sides.

At the start of the lesson students recap working with order of operations, squares and square roots. The plenary challenges students to apply Pythagoras' Theorem to test whether a triangle is a right-angle or not.

**Differentiated Learning Objectives**

- All students should be able to calculate the squared area of each edge of a right-angled triangle.
- Most students should be able to calculate the hypotenuse length of a right-angled triangle.
- Some students should be able to use Pythagoras’ Theorem to determine whether a triangle has a right-angle.