This lesson focuses on the topic of Pythagoras' theorem and the laws surrounding right-angled triangles. Showing how to apply/ use the Pythagoras formula in a step-by-step way, this lesson is designed to be interactive, with questions/ answers included. This also reduces the need for printing. Although originally designed for a UK GCSE level class, this resource will prove useful in any math lesson. Learning aims are also included so students can measure their level of understanding and success in class. A lesson I have enjoyed teaching myself!