A right triangle has a total of 180 degrees in its interior angles, just like any other triangle. However, what defines a right triangle is that one of its angles is exactly 90 degrees.
This means that the remaining two angles must add up to 90 degrees as well, since the sum of all angles in a triangle is always 180 degrees. For example, if one of the other angles is 30 degrees, the third angle would be 60 degrees. Thus, a right triangle specifically contains one right angle (90 degrees) and two other angles that are acute (less than 90 degrees) and combine to 90 degrees.