4-4 Similar Figures and Proportions
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Congruent polygons have the same shape & size.
~
Similar polygons have the same shape.
In similar polygons, all corresponding angles are
congruent and all sides are proportional.
4-4 Similar Figures and Proportions
The similarity ratio (also called the scale factor) is the ratio
of the lengths of the sides in two similar polygons.
3
2
6
4
6
4
The similarity ratio is 3:2
1
4-4 Similar Figures and Proportions
Decide whether the figures are similar or not.
1)
A
12
B
16
L
K
100
100o
12
9
16
12
o
80
D
15
C
o
80o
M
J
20
4-4 Similar Figures and Proportions
Decide whether the figures are similar or not.
28
2)
21
113o
18
24
26o
41o
40
26o
30
2
4-4 Similar Figures and Proportions
Decide whether the figures are similar or not.
3
3)
16
10
10
5
5
16
3
4-4 Similar Figures and Proportions
Decide whether the figures are similar or not.
15
4)
120
o
8
10
114o
5
60o
20
10
3
4-4 Similar Figures and Proportions
These two figures are similar. Find x and y:
5)
10
y
9
8
x
20
24
4-4 Similar Figures and Proportions
4