Answer: 90 degrees
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Explanation:
Let x and y be the two angles. Because they are supplementary angles, this means x+y = 180. Also since we're told that the angle is its own supplement, we can say that y = x.
Consequently, we can replace y with x and solve for x like so:
x+y = 180
x+x = 180 .... y is replaced with x since y = x
2x = 180
2x/2 = 180/2
x = 90
This means y = 90 as well. As a check, note how
x+y = 90+90 = 180
which verifies our answer.
