1. 4.2 Congruent Triangles October 11, 2011
4.2 Congruence & Triangles
Congruent Figures: all of the parts in 1 figure are ≅ to the
corresponding parts of the other.
HW pg. 228 #3­15 odd, 19­21 & 26 1

2. 4.2 Congruent Triangles October 11, 2011
HW pg. 228 #3­15 odd, 19­21 & 26 2

3. 4.2 Congruent Triangles October 11, 2011
Third Angle Theorem
If 2 angles in one ∆ are = in measure to 2 angles of another ∆,
then the 3rd angle in each triangle are ≅ .
B E
<A ≅ <D & <B ≅ <E;
therefore <C ≅ <F
C F
A D
HW pg. 228 #3­15 odd, 19­21 & 26 3

4. 4.2 Congruent Triangles October 11, 2011
HW pg. 228 #3­15 odd, 19­21 & 26 4

5. 4.2 Congruent Triangles October 11, 2011
Theorem 4.4 Properties of Congruent Triangles
Reflexive: ABC ≅ ABC
Symmetric: If ABC ≅ DEF, then DEF ≅ ABC
Transitive: If ABC ≅ DEF & DEF ≅ JKL,
then ABC ≅ JKL
HW pg. 228 #3­15 odd, 19­21 & 26 5

6. 4.2 Congruent Triangles October 11, 2011
HW pg. 228 #3-15 odd, 19-21 & 26
HW pg. 228 #3­15 odd, 19­21 & 26 6