| A | B |
|---|
| Triangle | 3-sided polygon |
| Scalene | No sides congruent |
| Isosceles | 2 sides congruent |
| Equilateral | All sides congruent |
| Acute Triangle | All angles between 0 & 90 degrees |
| Right Triangle | One angle exactly 90 degrees |
| Obtuse Triangle | One angle between 90 & 180 degrees |
| Equiangular Triangle | All angles exactly 60 degrees |
| Interior Angle | "Inside" the rays |
| Exterior Angle | Forms a linear pair with an interior one |
| Corollary | Easily proven using a Theorem |
| Congruent | Same size and shape |
| Corresponding | "Matched up" parts |
| Hypotenuse | Across from the right angle |
| Legs | Forming the right angle |
| Legs | Forming the Vertex Angle |
| Base | Across from the Vertex Angle |
| Base Angles | Also congruent in an Isosceles Triangle |
| Transformation | Changes location and size |
| Congruence Transformation | Changes ONLY location, not size |
| Translation | Slide |
| Reflection | Flip |
| Rotation | Turn |
| SSS Congruence Postulate | Involves all 3 sides |
| SAS Congruence Postulate | Involves the included angle |
| ASA Congruence Theorem | Involves the included side |
| AAS Congruence Theorem | Involves the non-included side |
| HL Congruence Theorem | Only applies to right triangles |
| Triangle Sum Theorem | Involves angles adding up to 180 degrees |
| Exterior Angle Theorem | Involves the 2 remote interior angles |
| Third Angles Theorem | Proves something about the "remaining" angle |
| Isosceles | Equilateral Triangles are also this |
| Equiangular | Equilateral Triangles are also this |
| Equilateral | Equiangular Triangles are also this |
| Base Angles Theorem | Applies to Isosceles Triangles |
| HL Congruence Theorem | a.k.a. SAS for rt. triangles |
| Ninety Degrees | Sum of acute angles in a rt. tri. |
| Supplementary | Interior and adjacent exterior angles |
