# Geometry/Properties

**Triangle Properties**[edit | edit source]

**Side-Side-Side (SSS) (Postulate 12) **
If three sides of one triangle are congruent to three sides of a second triangle, then the two triangles are congruent.

**Side-Angle-Side (SAS) (Postulate 13) **

If two sides and the included angle of a second triangle, then the two triangles are congruent.

'*Angle-Side-Angle'*** (ASA)**

If two angles and the included side of one triangle are congruent to two angles and the included side of a second triangle, then two triangles are congruent.

'*Angle-Angle-Side'*** (AAS)**

If two angles and a non-included side of one triangle are congruent to two angles and the corresponding non-included side of a second triangle, then the two triangles are congruent.

**NO - Angle-Side-Side (ASS)**

__The "ASS" postulate does not work__, unlike the other ones. A way that students can remember this is that "ass" is not a nice word, so we don't use it in geometry (since it does not work).