Reflex Angle

Pronunciation: /ˈri.flɛks ˈæŋ.gəl/ Explain

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Can you find all 5 angle classes represented?
Manipulative 1 - Angle Classes Created with GeoGebra.

Angles are divided into four classes according to their measure. A reflex angle is an angle that measures more than 1/2 of a full circle and less than afull circle.

Classes of Angles
Degree MeasureRadian MeasureClass Name
α < 90° α < π/2 rad. Acute angle
α = 90° α = π/2 rad. Right angle
90° < α < 180° π / 2 < α < π rad. Obtuse angle
α = 180° α = π rad. Straight angle
180 < α < 360° π < α < 2π rad. Reflex angle
α = 360° α = 2π rad. Full angle
Table 1: Classes of angles


  1. McAdams, David E.. All Math Words Dictionary, reflex angle. 2nd Classroom edition 20150108-4799968. pg 153. Life is a Story Problem LLC. January 8, 2015. Buy the book
  2. reflex angle. Encyclopedia Britannica. Merriam-Webster. Last Accessed 12/4/2018. angle. Buy the book

Cite this article as:

McAdams, David E. Reflex Angle. 5/2/2019. All Math Words Encyclopedia. Life is a Story Problem LLC.

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Revision History

5/2/2019: Changed equations and expressions to new format. (McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)
12/4/2018: Removed broken links, updated license, implemented new markup, implemented new Geogebra app. (McAdams, David E.)
8/7/2018: Changed vocabulary links to WORDLINK format. (McAdams, David E.)
12/14/2009: Expanded table of angle classes. (McAdams, David E.)
9/16/2008: Initial version. (McAdams, David E.)

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