# Central Angle

### Done By : Farah Ibrahim

## What is a central angle?

A central angle is an angle whose vertex is O of a circle and whose legs are radii intersecting the circle in two distinct points A and B.The central angle is substended by an arc between those two points.

## history of angles

EUCLID defines a plane angle as the inclination to each other ,in a plane,of two lines which meet each other,and do not lie straight with respect to each other.According to Proclus an angle must be either by a quality or quantity or a relationship.The first conceptwas used by Eudemus,who regarded an angle as a deviation from a straight line the second by Carpus of Antioch ,who regarded it as the interval or space between the intersecting line;Euclid adopted the third concept,although his definitions of right,acute,and obtuse angles