Download Name: _______________________ Date:_____ Period:____ Similar Triangle Proofs: Day 1

Name: _______________________
Similar Triangle Proofs: Day 1
Date:_____ Period:____
Ms. Anderle
Similar Triangle Proofs
Remember: Two triangles are similar if their corresponding angles are congruent
and the lengths of corresponding sides are proportional.
In order to prove two triangles similar in a formal proof is to prove two angles of
one triangle similar to two angles of the other triangle. This leads us to the AngleAngles (AA) Similarity Postulate: If two angles of one triangle are congruent to
two angles of another triangle, then the two triangles similar.
Examples:
1) G
Given: <G  <K
L
J
Prove: ΔHGL ~ ΔJKL
K
H
2)
A
Given: AB || DE
D
C
Prove: ΔABC ~ ΔEDC
E
B
3)
A
Given: AC  DC
AC  AD
B
C
Prove: ΔABD ~ ΔDBC
D
4)
M
Given: MA || MS
TG || HG
Prove: ΔMAS ~ ΔTGH
G
A
5)
T
H
S
M
Q
A
T
Given: ΔMTH ~ ΔQSP
RS bisects <QSP
AT bisects <MTH
R
H
S
Now: go to page 307 #’s 4, 8, 9, 14
Prove: ΔMAT ~ ΔQRS
P