Chapter 6: Lines and Angles

Types of Angles

Classification by Measure

TypeMeasure
Acute0°<θ<90°0° < \theta < 90°
Rightθ=90°\theta = 90°
Obtuse90°<θ<180°90° < \theta < 180°
Straightθ=180°\theta = 180°
Reflex180°<θ<360°180° < \theta < 360°

Angle Pairs

Complementary: Sum = 90°90° Supplementary: Sum = 180°180° Linear Pair: Adjacent angles on a straight line