We are given that the measure of one angle is equal to 115 degrees (for convenience, we’ll refer to this angle as ∠W). Looking at the image above, we can see that ∠W and ∠Y are supplementary angles. Supplementary angles are two angles whose measures add to a sum of 180 degrees, also known as a straight line. This relationship can be expressed using the following formula:
A1 + A2 = 180
Now insert any known values provided by the image above:
(115) + (∠Y) = 180
Subtract 115 from both sides of the equation:
∠Y = 65
We have now proven that ∠Y has a measure of 65 degrees. Now, looking at the image again, we can see that ∠W and ∠X are vertical angles. Vertical angles are two angles that lie on opposite sides of two intersecting lines. A pair of vertical angles is always equal in measure. This relationship can be expressed using the following formula:
A1 = A2
Now insert any known values provided by the image above:
(∠X) = (115)
We have now proven that ∠X has a measure of 115 degrees.
