12.4 Similar Triangles and Similar Figures

Recall the meaning of similar—the shape is the same but the size may be different

Def. __Scale Factor__—ratio of the corresponding side
lengths of a figure.

Def. __Similar Triangles__--∆ABC ~ ∆DEF iff _{}A is congruent to _{}D, _{}B is congruent to _{}E, _{}C is congruent to _{}F __and___{}.

**ANGLE/ANGLE PROPERTY**

AA versus AAA?????? –we only need two angles to prove similarity—this is if two angles of one triangle are congruent respectively to two angles of a second triangle, then the triangles are similar.

Example

**THEOREMS**

_{} look at theorems