(1) The angle which is less than 90 degree is called acute angle.
(2) The angle which is 90 degree is called right angle.
(3) The angle which is more than 90 degree is called obtuse angle.
(4) Angle whose measure exactly 180 degree is called complementary angle.
(5) Two Angles are Complementary when they add up to 90 degrees.
(6) Two angle are supplementary when they add up to 180 degree.