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8.4 Congruences and Proportions in Similar Triangles.notebook December 11, 2015Mental Floss: Fri, Dec 4thFind all missing side lengths in the similar figures below.
5
AB
CD
6
W
X
Y
Z
9
14
12
Given:
S
L I
K T
N O
P
Find:
46o
20
87o
104o
1232
22
a.)
b.)
c.) TO
8.4 Congruence and Proportions
Similar Polygons:
1.) Corresponding angles congruent
2.) Corresponding sides proportional
106
8
159
12
~
Theorem 1: The ratio of the perimeters of two similar polygons is equal to the ratio of any two corresponding sides.
3 5L
A D
B
O Y
Ratio of sides:
Ratio of perimeters:
Theorem 2: The ratio of the areas of two similar polygons is equal to the ratio of any two corresponding sides squared.
Ratio of areas:
Shadow problem #1A radio antenna that is 100 meters tall casts a shadow that is 80 meters long. At the same time, a nearby telephone pole casts a 16 meter shadow. What is the height of the telephone pole?
Sun
A tree 33 ft tall is casting a shadow into an open field. A 6 ft tall man is standing so the sun is just barely touching the top of his head. If the man is 23 ft away from the tree, find:
1. The length of the shadow of the tree
2. The length of the man's shadow if the tree was taken away.
Shadow problem #2
8.4 Congruences and Proportions in Similar Triangles.notebook December 11, 2015