What did you include in your response? Check all that apply.
Sample Response: Because vertical angles are
congruent, angles 1 and 4 are congruent. Because
corresponding angles are congruent, angles 4 and 8 are
congruent. Because angle 4 is congruent to both 1 and 8,
angle 1 is congruent to angle 8.
vertical angles theorem
corresponding angles theorem
transitive property
supplementary angles
linear pairs

1. The first theorem used is that vertical angles are congruent.

2. The next theorem used is that adjacent angles in a parallelogram are supplementary.

3. The definition of supplementary angles is then used for angle formed by intersecting  lines.

4. The theorem on vertical angles is used again.

5. Finally, the definition of the transitivity property is used to prove that alternate exterior angles are congruent.

it has to have an angle of 90 degrees

can you take a photo of the screen?