Question

Which one of these four triangles is not similar? Explain how you know. Write a few

sentences and be sure to explain completely.

Answer 1

Triangle D is different.

Every triangle is right-angled except for triangle D.

Proof for the 3rd angle of triangle D:

120+30+x = 180

150+x = 180

x = 30

Therefore, we can prove that there are no right angles in triangle D.