Geometry Proof Worksheet (3) - Practice problems for proving angle relationships using given information.

1. Since ∠3 ≅ ∠4 (given), and ∠1 and ∠3 are supplementary (linear pair), and ∠2 and ∠4 are supplementary (linear pair), then ∠1 ≅ ∠2 by the Congruent Supplements Theorem.

2. Since ∠1 ≅ ∠4 (given), and ∠1 and ∠2 are vertical angles, and ∠3 and ∠4 are vertical angles, then ∠2 ≅ ∠3 by the Vertical Angles Theorem and substitution.

3. Since ∠1 ≅ ∠3 (given), and ∠1 and ∠2 form a linear pair (supplementary), then ∠2 is supplementary to ∠3 by substitution.

4. Since ∠4 ≅ ∠6 (given), and ∠5 and ∠4 are vertical angles, then ∠5 ≅ ∠6 by the Vertical Angles Theorem and substitution.