Use the vertices of triangle ABC and triangle DEF to show that angle A is congruent to angle D. Explain your reasoning.

9. A(1,2), B(4, -3), C(2,5), D(4,7), E(7,2), F(5, 10)

10. A(2,3), B(2,9), C(6,6), D(8,5), E(8, 11), F(12,8)