| A | B |
|---|
| Median | Line connecting vertex to midpoint of opposite side |
| Angle Bisector | Line that divides an angle into two equal parts |
| perpendicular bisector of triangle | Line perpendicular to a side cutting it into two equal parts |
| Altitude of triangle | Line from vertex of a triangle perpendicular to the opposite side or its extension |
| Scalene triangle | Triangle with no sides equal |
| Isosceles triangle | Triangle with at least two sides equal |
| Incenter | The point at which the angle bisectors meet |
| Circumcenter | The point at which the perpendicular bisecotrs meet |
| Orthocenter | The point at which altitudes meet |
| Centroid | The point at which medians meet |
| Triangle inequality | The sum of any two sides of a triangle is greater than the third side |
| Pythagorean theorem | In a right triangle, the sum of the squares of the legs is equal to the square of the hypotenuse. |
| Equilateral triangle | Triangle with all sides equal |
| Right triangle | Triangle with one 90 degree angle |
| Obtuse triangle | Triangle with an angle greater than 90 degrees |
| Acute triangle | Triangle with all angles less than 90 degrees |
