Required: To prove that opposite angles of a parallelogram are congruent.
1. Given ( opposite sides of a parallelogram are parallel)
2. Adjacent angles of a parallelogram are supplementary.
3. Given (opposite of a parallelogram are parallel)
4. Adjacent angles of a parallelogram are supplementary.
5. Congruency property
6. Transitive property
7. Congruency
8. Transitive property
9. Transitive property
10. Congruency