Area of Composite Shapes


Learning Intention: “Establish the formulas for areas of rectangles, triangles and parallelograms and use these in problem solving. Recognise and solve problems involving simple ratios.”

Success Criteria: Students will be able to calculate the area of various 2D shapes, including triangles, squares, rectangles and composites of these shapes. They will draw a house plan to scale and calculate the floor area of the house.

Homework: Measure the length and width of your bedroom and one other room in your house in meters. Notice that your doorways are about 1.0 meter wide.

Today’s task is to draw a scale plan of a holiday house. A rough estimate of the cost to construct a home is at least $1,000 per square meter. Your budget is $250,000, so the house must be less than 250 square meters in area. Use a scale – 1.0m to 1.0cm is a good way to start. So, 1.0cm on the plan, represents 100cm (1.0m) on the ground. Your scale is 1:100. Your holiday house should include the following rooms:

  • Lounge/Living area
  • Kitchen
  • Bathroom
  • 2 Bedrooms
  • Laundry



Assessment of Area and Perimeter

LC house plan

The assessment task for this unit of work is for you to draw the plans for a house, labelling the dimensions of each room and calculating the area of each room. The plans must be scale drawings, so you may like to have 1cm = 1m or 1:100. Your house should include at least two bedrooms, kitchen, lounge/living area, bathroom and laundry. Make sure you have allowances for door openings, wardrobes and hallways, if required. You can download an assessment rubric for this task at the Year 7 Wiki – Maths – Measurement Page.

JG house plan