Find the measure of an angle which forms a pair of supplementary angles with itself.

Explanation

Let us assume that angle is x.Now, the supplementary angle of this angle is equal to itself meaning the angle supplement to `x` is `x` itself.
We know that the sum of supplementary angles is equal to `180^@` so adding x with x and then equate it to `180^@`
`x+x=180^@`⇒`2x=180^@`
Dividing `2` on both the sides of the above equation we get
`x = 180^ @/2
⇒x=90^@`