Question Video: Finding the Measure of an Angle given Its Supplementary Angle’s Measure Mathematics • 7th Grade

Find the value of 𝑥.


Video Transcript

Find the value of 𝑥.

We’re given two angles on a straight line. We’re given the measurement of the first angle, which is 107 degrees, but we don’t know the measurement of angle 𝑥. You may have spotted that these two angles are on a straight line. We call two angles like this supplementary angles. They always add together to total 180 degrees.

So, we know the sum of the given angle, 107 degrees, plus 𝑥 total 180 degrees. We can use the inverse to help us find the answer. 180 degrees take away 107 degrees equals the measurement of angle 𝑥. 180 take away 107 equals 73. So, the value of 𝑥 is 73. We realized our two angles are supplementary angles, whose sum is 180 degrees. So, to find the value of 𝑥, we subtracted 107 degrees from 180 to give us our answer of 73.

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