Jazz draws a transversal, t, on two parallel lines AB and CD, as shown below: Two parallel lines are shown cut by a transversal labeled t. 1, 2, 7 and 8 are marked clockwise as exterior angles. 4, 3, 6, an

He makes the following table to prove that the alternate interior angles are equal:

Statement Justification
angle 2 = angle 6 Corresponding angles of parallel lines are congruent.
angle 2 = angle 4 ?
angle 4 = angle 6 transitive property of equality,
angle 2 = angle 6,
angle 2 = angle 4,
therefore angle 4 = angle 6
Which is the missing justification? (6 points)

Angles 1 and 3 are supplementary; therefore, angle 2 is equal to angle 4.
Alternate interior angles are congruent.
Vertical angles are congruent.
Angles 1 and 4 and angles 1 and 2 are congruent; therefore, angle 2 is equal to angle 4.