Any angle greater than 0 degrees but less than 90 degrees is called an acute angle
Angles that measure less than 90 degrees are called acute angles. Right angles measure exactly 90 degrees and obtuse angles are greater than 90 degrees.
90 degrees and 90 degrees
Angles that are less than 90 degrees are acute angles. Angles that are 90 degrees are right angles, and angles that are greater than 90 degrees are obtuse angles.
complementary angles
right angles
If you are asking what kind of angles add up to 90 degrees, the answer is complementary angles.
Two angles whose sum is 90 degrees are called complementary angles.
It is not a requirement that any of the angles are right angles (90 degrees), to qualify as a parallelogram.
Complementary angles.
there are an infinite amount of angle that measure less than 90 degrees; however, there are only 89 whole angles that measure less that 90.
If two angles of a triangle each measure 45 degrees, the third angle measures 90 degrees. This is because of the Triangle Sum Theorem - The sum of the measure of the interior angles of a triangle is 180 degrees. If you know that two of the angles total to be 90 degrees, you can subtract that 90 degrees from the total 180. The result is 90 degrees.
90 degrees