Complementary Angles

Definition: Complementary angles are two angles whose measures have a sum of 90°.

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Example: Find the measure of angle x that would make the pair of angles complementary.

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Solution: 

Use the information from the figure to find the value of angle x.

Step 1: We know a pair of complementary angles has a sum of 90°. Here our given angles measure 75° and x°. Using this information, write an equation that will allow us to solve for x.

75 + x = 90

Step 2: Solve for x:

75 + x = 90
x = 90 – 75
x = 15°

When angle x = 15°, the angles are complementary.

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