Which statements should be used to prove that the measures of angles 1 and 5 sum to 180°?
Answer choices: - Angles 1 and 8 are congruent as corresponding angles; angles 5 and 8 form a linear pair.
- Angles 1 and 2 form a linear pair; angles 3 and 4 form a linear pair.
- Angles 5 and 7 are congruent as vertical angles; angles 6 and 8 are congruent as vertical angles.
Angels 1 and 3 are congruent as vertical angles; angles 7 and 9 form a linear pair. |