“P. Sherman, 42 Wallaby Way, Sydney!”
7.2 Similar
Polygons
Similarity
Similar Polygons: Polygons having corresponding angles
congruent and corresponding sides proportional (denoted “~”).
1) Find mE
ABCD ~ EFGH
B
2) Find EH
G
C
72°
A
F
6in
D E
H
Similarity Ratio: The ratio of the lengths of corresponding sides in
similar polygons.
Similarity
Given LONM ~ QTSR below, find the value of x.
Determine whether the triangles are similar. If they are, write
a similarity statement and give the similarity ratio.
E
B
15
78° 12
16
78°
67°
A
18
C
20
35°
D
24
F
Similarity
Are the polygons similar? If they are, write a similarity
statement, and give the similarity ratio. If they are not, explain.
Similarity
The polygons are similar. Find the values of the variables.
Golden Ratio
GOLDEN RECTANGLE
ACTIVITY!!!!
Golden Ratio
Golden Rectangle: A rectangle that can be divided into a square
and a rectangle that is similar to the original rectangle. The Golden
Ratio is ≈ 1.618
An artist plans to paint a picture. He wants the canvas to be a
golden rectangle with its longer horizontal sides 30cm wide.
How high should the canvas be?
“Onions have layers.”
7.2 Similar
Polygons
HW 7.2: #2-12 even, 13-16,
21-28, 32-35
THT: #1-4, 16, 18-25