9-7:Congruent and Similar Figures

Congruent Figures

Similar Figures

Congruent Figures

1. Which of these figures are congruent to the yellow one?

2

5

4

3

1

76

8

AnswersHints

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Congruent figures are all shown in yellow – were you right?

5

4

3

1

76

8

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2

What makes a pair of figures “congruent”?

Congruent figures have the same size and shape.

They have corresponding sides that are congruent.

Can be rotated or a mirror image

A cut-out of one shape will always fit exactly over the other

Click the green box if you want to go back to the first “congruent shapes” question page.

Question page

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2. Which of these figures are congruent to the yellow one?

Answers

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2

5

1

3

4

6

7

8

9

Congruent figures are all shown in yellow – were you right?

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2

5

1

3

4

6

7

8

9

Similar Figures

Which of these figures are similar to the yellow one?

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5

4

3

1

76

8

AnswersHints

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Similar figures are all shown in yellow – were you right?

2

5

4

3

1

76

8

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What makes a pair of figures “similar”?

Similar figures have the same shape but not necessarily the same size.Same corresponding anglesThey have corresponding sides that are proportional.Can be rotated or reflected

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Using similarity

9cm 12cm

6cm

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Since figures are similar, their sides are in the same proportion

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=> 9 = 3 12 4

=> 6 = 3 8 4

Equal Proportions - SimilarNot Equal Proportion – NOT Similar

Which of these figures are similar to the yellow one?

(They aren’t drawn to scale)

4

3

2

1

5 6

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6

9

6

9

4

6

4.5

3

12

189

12

4

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Similar figures are shown in yellow – were you right?

Start page

9

6

5

6

9

64.5

3

3

12

18

1

9

12

46

4

2

4

8

Practice Time!P505 # 1-6