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Year 8

Checking understanding of area

I can find the area of triangles, quadrilaterals and composite rectilinear shapes.

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New
New
Year 8

Checking understanding of area

I can find the area of triangles, quadrilaterals and composite rectilinear shapes.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. The formula can be used to find the area of a triangle.
  2. There can be more than one way to find the area of a trapezium.
  3. The area of composite shapes can be found by splitting into shapes whose area can be found.

Common misconception

Pupils may find the area by multiplying lengths which are not perpendicular.

Area is measured in square units. The base and height of a square are perpendicular. We multiply perpendicular lengths to make square units.

Keywords

  • Area - The area is the size of the surface and states the number of unit squares needed to completely cover that surface.

  • Trapezium - A trapezium is a quadrilateral with exactly one pair of parallel opposite sides.

  • Trapeziums/trapezia - The plural of trapezium can be referred to as trapezia or trapeziums.

  • Composite rectilinear shape - A composite rectilinear shape is a composite shape made from rectangles.

The shapes in Task B are drawn to scale so that there is the option to explore the problem by cutting out the shapes, overlaying them on the trapezium and manipulating shapes to find alternative solutions.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Video

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Starter quiz

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6 Questions

Q1.
The is the size of the surface and states the number of unit squares needed to completely cover that surface.
angle
Correct answer: area
length
volume
Q2.
Which of these units are a measure of area?
m
Correct answer: m$$^2$$
m$$^3$$
Q3.
The area of the rectangle is m$$^2$$.
An image in a quiz
Correct Answer: 12, twelve
Q4.
Which line segments are perpendicular to each other?
An image in a quiz
Correct answer: A and B
A and C
B and C
Q5.
For which shape can the area be calculated by doing $${1}\over{2}$$ $$\times$$ base $$\times$$ perpendicular height?
parallelogram
rectangle
square
Correct answer: triangle
Q6.
Select the rectangle with the largest area.
An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz

Exit quiz

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6 Questions

Q1.
The area of the rectangle is units$$^2$$.
An image in a quiz
Correct Answer: 30, thirty
Q2.
The area of the parallelogram is units$$^2$$.
An image in a quiz
Correct Answer: 12, twelve
Q3.
The area of the triangle is units$$^2$$.
An image in a quiz
Correct Answer: 18, eighteen
Q4.
A is a quadrilateral with exactly one pair of parallel opposite sides.
parallelogram
rectangle
rhombus
square
Correct answer: trapezium
Q5.
The formula $$A=$$ $${1}\over{2}$$ $$\times (a + b) \times h$$ can be used to calculate area of a trapezium. Which calculation is correct for finding the area of the trapezium?
An image in a quiz
$${1}\over{2}$$ $$\times (5 + 6) \times 7$$
Correct answer: $${1}\over{2}$$ $$\times (5 + 7) \times 6$$
$${1}\over{2}$$ $$\times (6 + 7) \times 5$$
Q6.
This compound shape is made from a rectangle and a triangle. Its area is units$$^2$$.
An image in a quiz
50
Correct answer: 65
80
400