This is a maths problem on surface area, ideal for use as a lesson starter with KS3 classes. The clip is shot in a shopping centre to provide an engaging, real-life context for the maths. The problem: The shopping-centre floor has an eye-catching design: an equilateral octagon, each side measuring 6 metres. Students must calculate the surface area of the octagon. Maths expert Isaac Anoom gives three examples of how the problem could be tackled: The first example is to separate the octagon into smaller shapes - 1 square, 4 right-angled isosceles triangles and 4 rectangles. The second example is to think of it as a big square with 4 right-angled triangles cut off. Thirdly, one could divide the octagon into eight isosceles triangles, then divide 360 by 8 and work out the area of the triangle using Pythagoras. This method works for any regular polygon.

Video Series: Shopping Mall
Release Date 2009