Coterminal Angles

Two angles a are coterminal if their sum is a multiple of 360°. What that means is that two angles are coterminal when they start and end in the same place. Examples of Coterminal angles are

• 180° and − 180°
• 170° and − 190°
• 100° and − 260°
• 360° and 720 °
• 360° and − 360°