Identify Complementary and Supplementary Angles
Complementary Angles: Learn
Two angles are complementary if the sum of their angles equals 90° (they add up to a right angle).
If one angle is known, its complementary angle can be found by subtracting the measure of its angle from 90°.
Example: What is the complementary angle of 43°?
Solution: 90° - 43° = 47°
Two angles are supplementary if the sum of their angles equals 180° (they add up to a straight line).
If one angle is known, its supplementary angle can be found by subtracting the measure of its angle from 180°.
Example: What is the supplementary angle of 43°?
Solution: 180° - 43° = 137°
Complementary and Supplementary: Practice
Are the angles complementary, supplementary, or neither?
00:00Angle A is °
Angle B is °
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