Complementary.
complementary
If you are asking what kind of angles add up to 90 degrees, the answer is complementary angles.
acute
An obtuse angle
Right Angle! (:
Complementary.
That would be a right angle: The measure of complementary angles adds up to 90 degrees. Adjacent angles are angles that share one common side and one common vertex, but no common interior points (the angles don't overlap). The non-common sides of two adjacent angles are the two "outside" sides (the unshared sides). Two adjacent and complementary angles would form a right angle split by a ray/line, and not necessarily bisected (perfectly divided in half).
this is called vertical angles
If you bisect an angle, you are dividing it in half, thereby producing two smaller, but equal angles.
complementary
hi
If you are asking what kind of angles add up to 90 degrees, the answer is complementary angles.
acute
Straight Angle :)
An obtuse angle
Acute angles