Make: Geometry

prove that the three angles are the same in all three triangles is to overlay

them, with the relevant angle lined up.

Note that similar triangles have the same set of angles, but are not (neces-

sarily) congruent because they may be different sizes, as we see here. If the

sizes of the triangles were the same, they would indeed be congruent, so

congruent triangles are a special case of similar triangles. Here we can see

these three triangles all have at least one angle in common (Figure 5-16).

Mixing the three scaled triangles still allows you to create a straight line out of

the angles, just as we saw in the exercise where we lined up the thr ...