Question Use facts about supplementary angles to solve the following problem. Two angles are supplementary and have measures m∠ABC=15° and m∠CBD=x° . What is the value of m∠CBD ?
Since two angles are supplementary, their measures add up to 180°. Therefore, the measure of angle CBD can be found by subtracting the measure of angle ABC from 180°:
m∠CBD = 180° - m∠ABC
m∠CBD = 180° - 15°
m∠CBD = 165°