Angle: An angle is made when two rays start from the same endpoint. Interior of an Angle : All places in the plane of BAC that are located on either side of the AB-C and AC-B lines are considered to be in the angle's intramural. Obtuse Angle: An obtuse angle is one that is bigger than 900 but smaller than 1800. Reflex Angle: A reflex angle is an angle that is bigger than 1800 but smaller than 3600. Complementary angles: Two angles are said to go together when the sum of their measures is 900. Supplementary Angles – When the sum of the measurements of two angles equals 1800, they are said to be supplementary.