Problem 168
If the triangles are similar, write a similarity statement and give a reason why they are similar. If not, indicate “not similar.”
Solution
Two triangles are similar when their internal angles are congruent.
(Evidently, the third angle in both triangles is also congruent, since its size is constrained by the sum of the internal angles having to equal 180°.) In the case of the figure, angles C and A are congruent with angles F and D, respectively. Hence, both triangles are similar.