What is enough to guarantee two triangles are similar?

Author:
dthurston
Topic:
Triangles
Two figures are similar if one is a "blown up" or "shrunken" version of the other. If this is the case, we should be able to create the pink triangle by moving and shrinking/enlarging the white one.

Slide the slider to see if we have enough evidence to say that these triangles are similar!

Here we have two triangles which have two pairs of proportional sides with the same angle between them. When we slide the slider, this moves and enlarges the smaller triangle. Is there evidence here to guarantee these two triangles are similar?
In this image, we are given two triangles with 3 sets of proportional sides. When you slide the slider, does anything happen that suggests these triangles might be similar? If so, what is it?