Year 11
Higher

Year 11
Higher

# Find areas of similar shapes given corresponding lengths

## Lesson details

### Key learning points

1. In this lesson, we will use the linear scale factor to calculate the area scale factor and find areas of similar shapes.

### Licence

This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.

## Video

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## Worksheet

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## Starter quiz

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### 3 Questions

Q1.
Shape A maps to shape B in an enlargement, calculate the scale factor.
-1
1
2
Q2.
Why have corresponding vertices been joined up in shapes A and B with straight lines in this enlargement?
They do not do anything useful.
They get extra marks in a test.
Correct answer: They help with finding the centre of enlargement.
Q3.
The point at (-2,-1) is enlarged by a scale factor of -2 from the centre of enlargement at (0,0). What will the new coordinate of the point be?
(-4,-2)
(0,0)
(2,1)

## Exit quiz

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### 4 Questions

Q1.
Shape A and shape B are similar. Calculate the area of shape B.
120 cm²
144 cm²
Correct answer: 240 cm²
30 cm²
Q2.
Two similar triangles have heights of 2 cm and 10 cm. The area of the smaller triangle is 5 cm². Calculate the area of the larger triangle.
10 cm²
Correct answer: 125 cm²
20 cm²
25 cm²
Q3.
Complete the missing word:
eight
four