In this lesson, students use Pythagoras’ theorem to find accurate values for the perimeters of some triangles. Although the values of the perimeters are so close that it would be very hard to distinguish them by measurement, mathematics makes it possible to be absolutely sure about the order in which they come.
For more Colin Foster geometry and measures lesson plans click here.
Sign up here for your free Brilliant Teacher Box Set
Get 8 KS3/4 maths lessons with expert teaching techniques