11. ∠7≅∠3 is true because alternate interior angles of two parallel lines cut by a transversal line are congruent.
12.∠7≅∠6 is not true because these two angles are supplementary to each other which means ∠7 + ∠6 = 180 degrees.
13. ∠3 and ∠1 are corresponding angles and corresponding angles are congruent.
m∠3 = m∠1
15x + 22 = 19x - 10
15(8) + 22 = 19(8) - 10
120 + 22 = 152 - 10
142 = 142
Since both m∠3 and m∠1 gave us the same measure of the angle which is 142 degrees, this proves that corresponding angles in this figure are congruent. Therefore, #13 is true.
Since ∠7≅∠3 and m∠3 = m∠1, lines m and n are parallel.