Geometry · Points, Lines & Angles
Obtuse Angle
HSG-CO.A.1
Definition
An angle that measures greater than 90 and less than 180 degrees.
Examples
- 120 degrees is an obtuse angle.
- 150 degrees is an obtuse angle.
Key rule
An obtuse angle is always wider than a right angle but not a straight line.
Memory hook
Wider than a right angle, but not flat.