A simple polygon that is not convex is called concave,[1] non-convex[2] or reentrant.[3] A concave polygon will always have at least one reflex interior angle—that is, an angle with a measure that is between 180 degrees and 360 degrees exclusive.[4]
- ^ McConnell, Jeffrey J. (2006), Computer Graphics: Theory Into Practice, p. 130, ISBN 0-7637-2250-2.
- ^ Leff, Lawrence (2008), Let's Review: Geometry, Hauppauge, NY: Barron's Educational Series, p. 66, ISBN 978-0-7641-4069-3
- ^ Mason, J.I. (1946), "On the angles of a polygon", The Mathematical Gazette, 30 (291), The Mathematical Association: 237–238, doi:10.2307/3611229, JSTOR 3611229.
- ^ "Definition and properties of concave polygons with interactive animation".