Carlos 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, and 5 are marked clockwise as interior angles
he makes the following table to prove that the alternate interior angles are equal:
statement justification
angle 1 = angle 5 corresponding angles of parallel lines are congruent.
angle 1 = angle 3 ?
angle 3 = angle 5 transitive property of equality,
angle 1 = angle 5,
angle 1 = angle 3,
therefore angle 3 = angle 5
which is the missing justification?