New
New
Calculate the area of compound rectilinear shapes
I can calculate the area of compound rectilinear shapes.
Lesson 6 of 10
New
New
- Year 5
Calculate the area of compound rectilinear shapes
I can calculate the area of compound rectilinear shapes.
Lesson details
Key learning points
- Use addition and subtraction to calculate missing side lengths in compound rectilinear shapes.
- Identify two different lengths which total another side length in a compound rectilinear shape.
- Use knowledge of the area of a rectangle to calculate the area of shapes made from two rectangles.
Keywords
Compound - A shape made up of two or more other shapes is known as compound.
Rectilinear - A shape where all angles composed of right angles is called a rectilinear shape.
Common misconception
Calculating the length of a side when the overall dimension and part dimensions are known and understanding when a part of the overall dimension is needed to calculate part of the area.
Look at shapes with missing dimensions and discussing that the overall length and width of a compound rectilinear shape is the total of the shorter side lengths in a particular direction. This allows missing or overall dimensions to be calculated.
Consider the dimensions of the shapes without calculating the area to ensure that pupils are confident in reasoning about missing dimensions before applying them when splitting up compound shapes in order to calculate the area. Allow time to explore the different ways that shapes can be split.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Match the start and end of the sentences to describe the shapes correctly.
Match the start and end of the sentences to describe the shapes correctly.
Q2.The area of a compound shape made of two rectangles can be calculated by the area of each rectangle.
The area of a compound shape made of two rectangles can be calculated by the area of each rectangle.
dividing
multiplying
Q3.What is the total area of this compound rectilinear shape? m².
What is the total area of this compound rectilinear shape? m².
Q4.Which times table fact is needed to calculate the missing area in this rectilinear shape?
Which times table fact is needed to calculate the missing area in this rectilinear shape?
13 m x 8 m
8 m x 3 m
Q5.Which multiplications are needed to calculate the area of the shape?
Which multiplications are needed to calculate the area of the shape?
7 × 5
2 × 5
Q6.Calculate the area of this rectilinear shape? cm²
Calculate the area of this rectilinear shape? cm²
Assessment exit quiz
6 Questions
Q1.Match the parts of the sentences correctly.
Match the parts of the sentences correctly.
Q2.We can calculate the area of compound rectilinear shapes by splitting it into .
We can calculate the area of compound rectilinear shapes by splitting it into .
Q3.Look at this compound rectilinear shape. Which statements are true?
Look at this compound rectilinear shape. Which statements are true?
side a is 9 cm
I don't know the lengths of sides a and b
Q4.Look at this shape. The total length of sides a and d is cm.
Look at this shape. The total length of sides a and d is cm.
Q5.What is the missing length 'a' on this shape? cm
What is the missing length 'a' on this shape? cm
Q6.Calculate the area of this compound rectilinear shape. A = cm²
Calculate the area of this compound rectilinear shape. A = cm²
