The answer is acute angles.
Step-by-step explanation:
If a triangle is a right triangle, then the other two angles must be acute angles.
We know that the sum of a triangle is 180 degrees.
So, if one angle is 90 degrees or right angle, then the other two angles must be less than 90 degrees to form a total of 180 degrees.
And any angle less than 90 degrees is called an acute angle.
Therefore, the answer to the question is Acute angle.
