Which of the following triangles are similar?

One triangle has side measures , , and . Another has side lengths , , and . Are these triangles similar?

Are these triangles similar? If so, state the scale factor.

Are these triangles similar? If so, state the scale factor.

One triangle has side measures 2, 4, and 5. Another has sides 4, 8, and 10. Are these triangles similar?

What does the scale factor of a dilation need to be to ensure that triangles are not only similar but also congruent?

Which of the following is not a theorem to prove that triangles are similar?