When two lines intersect, they form four angles. If one angle measures 135 degrees, then the sum of all four angles is 360 degrees.
Let's call the other three angles A, B, and C. The sum of these three angles is equal to 360 degrees minus the given angle measure of 135 degrees.
A + B + C = 360 - 135 = 225 degrees.
Since the angles formed by intersecting lines are supplementary, we know that angles A, B, and C are acute angles because they add up to less than 180 degrees.