Definition of a reflex angle (one whose measure is greater than 180 degrees but less than 360 degrees).
Math Open Reference

Definition of an obtuse angle. An angle between (but not including) 90deg and 180 deg;
Math Open Reference

Defines what is meant by 'interior of an angle'
Math Open Reference

Included definition: Angle made by two lines with a common vertex.
Math Open Reference

Definition of a full angle. An angle whose measure is exactly 360°.
Math Open Reference

Definition and properties of complementary angles  two angles that add to 90 degrees
Math Open Reference

Use your knowledge of vertical angles and supplementary angles to find the measurements for all angles. Answers included.
MathDrills.com

Explanation and diagram of straight angles
Math is Fun

Explanation of obtuse angles
Math is Fun

Explanation and diagram of exterior angles.
Math is Fun
