Learn what angles are and how to measure them
An angle is formed when two rays share a common endpoint called the vertex.
Angles are measured in degrees (°).
| Type | Measure | Example |
|---|---|---|
| Acute | Less than 90° | 45°, 30°, 60° |
| Right | Exactly 90° | Corner of a square |
| Obtuse | Between 90° and 180° | 120°, 150° |
| Straight | Exactly 180° | A straight line |
| Reflex | Between 180° and 360° | 270°, 300° |
Angles can be named:
Two angles that add up to 90°
Two angles that add up to 180°
When two lines cross, opposite angles are equal.