One angle of a right triangle measures 21°. What is the measure of the other acute angle?

A triangle has 3 sides and angles (obviously) and we are given that this triangle is a right triangle, which means one of the angle is 90 degrees. We are then given another angle is 21 degrees. Now we need to find the last angle a triangle adds up to 180 degrees. So 90+21=111 degrees. 180-111=69 degrees. (nice)
The answer is 69 degrees (nice)
(This is not troll)