1. 4.6 Using Congruent Triangles
Corresponding parts of congruent triangles are congruent.
*Special case of definition of congruent figures.
*Used after proving triangles congruent.
CPCTC

2. Angles in a linear pair are ≡. Suppl. Of ≡ <s are ≡.
Statements Reasons
1. <1 ≡ <2
<ABC suppl. <1
<DEC suppl <2
3. < ABC ≡ < DEC
4. <ACB ≡ <DCE 5.
ACB ≡ DCE .
Given
Angles in a linear pair are ≡.
Suppl. Of ≡ <s are ≡.
Vertical <s are ≡ .
AAS ≡
CPCTC

3. The triangles are congruent
by ASA. CPCTC says that
AB= DE. If you can measure
length of DE, then you will
know the length of AB.

4. The supplements of < 1 and <2 are congruent. DE is reflexive.
∆ DEB ≡ ∆ DEC by AAS.
DB ≡ DC because of CPCTC.
AD is reflexive. This makes ∆ ABD ≡ ∆ ACD by SAS.

5. Geometry
Page 257(1-14, 28, 41-43)
Page 259 (18-24, 29-31, 33-35, 44-46)