Complete the
Bell Work
Handout
Bell Work
Write a congruence statement.
M
T
R
∆MNL ≅ ∆SRT
N
L
S
Similar Polygons
• Two objects are similar if they are the same
shape but different sizes.
Example:
Is the pair of polygons similar? Explain your answer.
5m
8m
10 m
13 m
5
8

10 13
5(13) = 10(8)
65 = 80
NO
OR
5 10

8 13
5(13) = 8(10)
65 = 80
NO
Example:
Is the pair of polygons similar? Explain your answer.
4 yd
3 yd
4.5 yd
6 yd
4
3

6 4 .5
4(4.5) = 6(3)
18 = 18
YES
OR
4
6

3 4 .5
4(4.5) = 6(3)
18 = 18
YES
Are the polygons similar? You must be able to justify
your answer. (Shapes not drawn to scale.)
Yes
No
15 ft
9 ft
12 ft
21 ft
Are the polygons similar? You must be able to justify
your answer. (Shapes not drawn to scale.)
Yes
No
10 m
8m
2.5 m
2m
Are the polygons similar? You must be able to justify
your answer. (Shapes not drawn to scale.)
Yes
No
15 yd
6 yd
37.5 yd
15 yd
Example:
Find the value of x in the pair of similar polygons.
15 cm
x
6 cm
10 cm
8 cm
15 6

x 10
15(10) = 6x
150 = 6x
25 cm = x
15 x

OR
6 10
15(10) = 6x
150 = 6x
25 cm = x
You try:
Find the value of y in the pair of similar polygons.
15 in
7.5 in
5 in
y
15 7.5

y
5
15(5) = 7.5x
75 = 7.5x
10 in = x
Or
15 y

7 .5 5
15(5) = 7.5x
75 = 7.5x
10 in = x
Find the measure of the missing value in the pair of
similar polygons. (Shapes not drawn to scale.)
17.5 ft
25 ft
25 ft
18 ft
A
18ft
B
450ft
C
12.6 ft
D
.07 ft
w
Find the measure of the missing value in the pair of
similar polygons. (Shapes not drawn to scale.)
x
4m
4.25 m
17 m
A
16m
B
16.25m
C
68ft
D
18.06ft
Find the measure of the missing value in the pair of
similar polygons. (Shapes not drawn to scale.)
y
6 mm
11 mm
A
66mm
B
70.58mm
C
33.5mm
D
21 mm
38.5 mm
Scale Factor
• When you compare
corresponding
measurements of
proportional objects,
you get a ratio.
• This ratio is called
the scale factor.
What is the scale factor from the
larger shape to the smaller one?
Practice:
Similar Polygons
Worksheet