# Composite shapes

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Learning Intention:  Understand that the area of all composite shapes can be calculated by breaking the shape down into known areas.

Success Criteria: You will be able to summarize the formulae to calculate the area of the following 2 dimensional shapes and break down a composite shape by identifying each of the known shapes and correctly calculating their area.

• squares and rectangles
• triangles
• parallelograms
• trapeziums
• circles and annuli

Some examples of these kinds of problems are in Exercise 8G (page 326) of MathsQuest8. Here are some other activities to learn about the area of composite shapes.

• An L-shaped room has a perimeter of 20m. What might the area of the floor be?
• The difference in areas of two rectangles is 32cm (squared). What might the widths and lengths of the two rectangles be?

Your homework (due Friday) is one of the following:

• Use Google Maps or Google Earth to find an aerial view of an unusual shape, take a screen shot and calculate it’s area using the scale measurements. Copy your screen shot into “Paint”, add the measurements, calculate the area and email it to me. You may choose a large building, carpark or arena (the MCG or Etihad stadium for example) or perhaps your farm or property.

## 2 thoughts on “Composite shapes”

• June 28, 2012 at 1:08 am