## Elementary Geometry for College Students (5th Edition)

Proof 1: $\overline{DC}$$\parallel$$\overline{AB}$ is given in question. Proof 2: $\angle$DCA is identical to $\angle$BAC because they are alternate interior angles Proof 3: $\overline{AD}$$\parallel$$\overline{BC}$ is given Proof 4: $\angle$DAC is identical to $\angle$BCA because if two $\parallel$ lines are cut by a transversal, alternate interior angles are identical. Proof 5: $\overline{AC}$ is identical to $\overline{AC}$ is identity Proof 6: $\triangle$ABC is identical to $\triangle$CDA because of ASA
Given: $\overline{DC}$$\parallel$$\overline{AB}$ and $\overline{AD}$$\parallel$$\overline{BC}$ To prove: $\triangle$ABC is identical to $\triangle$CDA