Question

find the angle of Stu so that both the angles can make complementary​

Answer 1

Answer:

In a right angled triangle, the two non-right angles are complementary, because in a triangle the three angles add to 180°, and 90° has already been taken by the right angle. When two angles add to 90°, we say they "Complement" each other.

Answer 2

Answer:

If two angles are complementary then they will add up to be 90, or inversely, if two angles add up to be 90, then they are complementary. If you know one acute angle, you can calculate its complementary angle by subtracting 90 and the angle.