year 8 maths

498 Chapter 8 Transformations and congruence
Example 10
5 Decide if these shapes are similar by considering corresponding angles and the ratios of sides.
a
A
E
10 cm F
b
D
12 cm
C
5 cm
13 cm
B
26 cm
D
24 cm
A
B
C
G
H
F
E
c
A
D
B
2 m
5 m
C
E
F
11 m
H
G
4 m
d
15 cm
5 cm
G
H
6 cm
F
2 cm
E
PROBLEM-SOLVING AND REASONING
6, 7, 10 7–11
7–10, 12
6 Two rectangular picture frames are similar in shape. A corresponding pair of sides are of length
50 cm and 75 cm . The other side length on the smaller frame is 70 cm . Find the perimeter of the
larger frame.
7 Two similar triangles have a scale factor of 7 . If the larger triangle has a side length of 35 cm , find
3
the length of the corresponding side on the smaller triangle.
8 One circle has a perimeter of 10π cm and another has an area of 16π cm 2 . Find the scale factor of
the diameters of the two circles.
9 A square photo of area 100 cm 2 is enlarged to an area of 900 cm 2 . Find the scale factor of the side
lengths of the two photos.
10 Are the following statements true or false? Give reasons for your answers.
a All squares are similar.
b All rectangles are similar.
c All equilateral triangles are similar.
d All isosceles triangles are similar.
e All rhombuses are similar.
f All parallelograms are similar.
g All kites are similar.
h All trapeziums are similar.
i All circles are similar.
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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