# Angle: An Illustrated Classification

The applet below illustrates the common classification of angles based an their angular measure. The applet illustrates both regular and signed angle types.

For unsigned angles,

- An angle is
*zero*if its two sides coincide and its interior is empty. - An angle is
*full*if its two sides coincide and its interior is the whole plane with a ray removed. - An angle is
*straight*if its two sides form a straight line. Either of the so formed half-planes may be the interior of the angle. - An angle is
*right*if when doubled it makes one straight angle. - An angle less than right is
*acute*. - An angle less than straight but greater than right is
*obtuse*. - An angle between straight and full is
*reflex*.

## Related material
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Copyright © 1996-2018 Alexander Bogomolny

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