| A | B |
|---|
| Acute Angle | An angle with a measure less than 90 degrees |
| Obtuse Angle | An angle with a measure greater that 90 degrees but less than 180 degrees. |
| Right Angle | A 90 degree angle. |
| Complementary Angle | Two angles whose sum of their measures is 90 degrees. |
| Supplementary Angle | Two angles whose sum of their measures is 180 degrees. |
| Straight Angle | An angle with a measure of 180 degrees. |
| Adjacent Angles | Two angles that share a vertex and a side. |
| Vertex | The point the two rays share, creating an angle. |
| Angle | Two rays with a common endpoint. |
| Line | Designated by two points with a double arrow over top, showing that it does not end in either direction. |
| Line Segment | Designated by two points with a short line over them to show that it has ending points on both sides. |
| Ray | Designated by two points with a single arrow over top, showing that it has a starting point on one end but does not end in the other direction. |
| Right Triangle | A triangle with a 90 degree angle. |
| Obtuse Triangle | A triangle with one angle over 90 degrees. |
| Acute Triangle | A triangle with three vertices with a measure less than 90 degrees each. |
| Scalene Triangle | A triangle with no congruent sides. |
| Isosceles Triangle | A triangle with at least two congruent sides. |
| Equilateral Triangle | A triangle with three congruent sides. |
