“Why so serious?”. 7.3 Proving Triangles Similar.
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Transcript of “Why so serious?”. 7.3 Proving Triangles Similar.
“Why so serious?”
7.3 Proving Triangles Similar
Similar Triangles
80° 40° 80° 40°
Postulate 7-1: Angle-Angle Similarity (AA ~) Postulate: If two angles of one triangle are congruent to two angles of another, then the triangles are similar.
TRS ~ PLM
Similar Triangles
R
W
S
B
V
Statements Reasons
1.
2.
3.
1.
2.
3.
RV
RSW VSB
RWS ~ VBS
Given : RVProve : RWS ~ VBS
Similar Triangles
Theorem 7-1: Side-Angle-Side Similarity (SAS ~) Theorem: If an angle of one triangle is congruent to an angle of a second, and the sides including the two angles are proportional, then the triangles are similar.
Theorem 7-2: Side-Side-Side Similarity (SSS ~) Theorem: If the corresponding sides of two triangles are proportional, then the triangles are similar.
Similar Triangles
If the following triangles are similar, state which postulate/theorem tells us. Then, find DE.
Real World ConnectionRamon places a mirror on the ground and walks back until he can see the top of the geyser in the middle of the mirror. Use similar triangles to find the height of the geyser.
Similar Triangles
In sunlight, a cactus casts a 9-ft shadow. At the same time, a 6-ft person casts a 4-ft shadow. Use similar triangles to find the height of the cactus.
Review
32
Simplify.
50
27
105
86
Review
2128
2
144
3
75
4125
“I feel the need… the need for speed!
HW (7.3) Pgs. 386-390; #1-19 odd, 31-39 odd, 41
7.3 Proving Triangles Similar