4.1 Congruent Polygons
Date:
Goals:
• Identify Congruent Corresponding parts
• Use third angle theorem
Congruent Polygons:
Corresponding Parts:
F
Example 1: Naming Corresponding Parts
Use the diagram to the right to answer the following given ABCD  HGFE
A. Name all corresponding angles.
B
A
G
B. Name all corresponding sides.
H
D
C
E
C. If mA  127 , what other angle will have the same measure?
Example 2: Determine if Polygons are Congruent
Determine if the following polygons are congruent.
A
A.
A
B.
8
12
E
C
B
12
8
B
C
Given: AB  DC , AD  BC , D  B , DAC  BCA
A
B
D
C
D
D
Third Angles Theorem:
Example 3: Prove Triangles are Congruent
Prove the following triangles are congruent.
Prove: ADC  CBA
Statement
1. AB  DC , AD  BC ,
D  B DAC  BCA
2. AC  AC
3. DCA  BAC
4. ADC  CBA
Reason