Answer:
90 degrees
Step-by-step explanation:
If two angles are supplementary they are a linear pair which means they form a straight line, and if you know a straight line equals 180 degrees which is the total degrees of a triangle.
Now if you have two supplementary angles and they are congruent that means not only are they right angles but its half of 180 so you divide these pair of 2 by 180 giving you your total of 90 degrees.
Have a nice rest of your day !
