Area of Circles and Composite Shapes

Programme Outline

Katie and Jamie need to use the formula for finding the area of a circle in order to compare pizza prices. They demonstrate how slices (sectors) can be used to show where the formula comes from and go on to calculate who has the most pizza on their plate.

On a visit to a factory we see how a drinks can starts life as a disc of metal and is then drawn out by machines to create the familiar object. This leading manufacturer produces over 6 million cans a day and the discs are stamped from a metal sheet. Jamie works out how much aluminium is left from each row of discs cut. He could now calculate how much the factory is saving per day by recycling all the waste immediately.

In this week's 'Tick or Trash', Katie and Jamie are asked to find the area of a path around a circular pond. By looking in detail at the calculation, Jamie explains how he went wrong.

Composite shapes can include semi-circles and quadrilaterals, but how do you spot them? We see how some complex shapes break down into simpler component shapes.

Exam questions often use real-life examples and one of the favourites is a running track with semi-circular ends. Katie and Jamie visit Don Valley Stadium and show how to find the area inside the track using only two measurements. If they were going to calculate the area of the track, what further measurements would they need to make?