7 2 Similar Polygons

Question: When are two polygons similar?
Answer: when their corresponding angles are congruent and side lengths are proportional
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Question: Find the scale factor of the ratio of the lengths of the corresponding sides of two similar polygons.
triangle ABC:
AB= 20
BC= 14
triangle DEF:
ED= x
EF= 6
Answer: triangle ABC~ triangle DEF
14/6 = 7/3
7/3 = 20/x
7(x)=7x
3(20)= 60
7x=60
x=8.57
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Question: what is the similarity of two polygons are similar, then their perimeters are proportional to the scale factor between them.
rectangle 1:
two parallel sides of 5
two parallel sides of 4
rectangle 2:
two parallel sides of 10
two parallel sides of 8
Answer: rectangle 1:
p=18
rectangle 2:
p=36
5/10=1/2
4/8= 1/2
18/36=1/2
pt=1/2=sf=1/2
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Question: is the scale factor of these polygons similar?
3/7.5
4/10
6/15
Answer: yes
0.4
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Question: true or false
-all squares are similar
Answer: true
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Question: true or false
-all isosceles triangles are similar
Answer: false
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Question: true or false
-all rectangles are similar
Answer: false
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Question: true or false
-all equilateral triangles are similar
Answer: true
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Question: true or false
-all rhombi are similar
Answer: false
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Question: true or false
-all regular pentagons are similar
Answer: true
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