Complementary Angles

Complementary Angles

How to solve complementary angles problems: formula, example, and its solution.

Example

If angle ABC and angle DEF are complementary angles, find the value of x. The measure of angle ABC = 30, The measure of angle DEF = 8x + 4.

Complementary angles are angles
whose sum of the angle's measures is 90.

It says these two angles are complementary.
So (30) + (8x + 4) = 90.