Calculating the Area of Composite Shapes (9)

Calculate the areas of composite shapes (ACMMG216)

LO:To find area of composite shapes.
Know:

  • the dimensions of 2-D shapes such as length and width (height).
  • the properties of 2-D shapes

Understand:

  • That formulas can be used to quickly find the area of composite shapes.
  • That composite shapes can be broken down to simple 2-D shapes.

Do:

  • I can find the area of composite shapes..

Area of Composite Shapes

Composite shapes are shapes that have a combination of 2-D shapes. To find the area of composite shapes you just need to break down the shape into individual pieces and calculate their separate pieces then add them back together again to find a total area.

Finding the Area of Composite Shapes (alternative methods)

Another way of finding the area of composite shapes is to use a subtraction model.

I could break the shape to the right into 2 pieces and find the area of the square then the area of the rectangle.

Alternatively, I can find the area of the entire shape (16 x 12) then subtract the missing piece (in pink) from the larger piece.

Teaching Ideas

Area of Composite Shapes Videos

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