Download 2 polygons are congruent if

Accelerated Geometry
8.2: Similarity
Name___________________
Date_______
B
Define Congruent Polygons:
2 polygons are congruent if and only if:
1.
2.
A
____________________________
G
F
C
E
H
J
____________________________
D
I
Symbol for Congruent:
K
Define Similar Polygons:
2 polygons are similar if and only if:
1.
______________________________
Q
P
L
M
O
T
2.
R
N
______________________________
S
Symbol for Similar:
E
Given: Quad BONE ~ Quad STAR
a. Corresponding angles:
∠B ≅ ∠ ______
∠O ≅ ______
∠N ≅ ∠ _____
∠E ≅ ______
b. Ratios of Corresponding Sides (with letters)
Quad BONE
= ________ = ________ = _______
Quad STAR
8”
T
B
A
5”
S
N
12”
12”
O
6”
R
c. Determine the scale factor:
d. Find the measure of remaining sides:
Method 1: Use Proportions
e. Find ratio of
Method 2: Use Scale Factor
PerimeterBONE
=
PerimeterSTAR
Conclusion: Ratio of Perimeters of 2 similar polygons is the same as ____________________.
Accelerated Geometry
8.2: Similarity
Name___________________
Date_______
A
S
60°
12”
5”
2.5”
W
50°
B
C
16”
60°
6”
70°
P
8”
Use the definition of similar polygons to determine if the triangles are similar.
1. Corresponding angles
△ABC ~ △______
2. Corresponding sides
Yes or No?
Practice:
1. Always, Sometimes, Never
a. ≅ polygons are ~ ________________
b. ~ polygons are ≅ _____________
2. Is each pair of figures described necessarily similar. Justify your answer. Draw a counter example
if it is possible for them to not be similar.
a. any two right triangles
b. any two congruent quadrilaterals
c. any two regular polygons
3. Draw and label a pair of polygons for each. If it is impossible to draw such figures, write
impossible.
a. two rectangles that are not similar
c. two rhombi that are not similar
b. two equilateral triangles that are not similar