# 5.1a Circles

     
   
5.1a Circles
   

   
5.1.1 Parts of a Circle
   
1. A circle is set of points in a plane equidistant from a fixed point.
   

   2.
Parts of a circle:
   
(a)    The centre, O, of a circle is a fixed point which is equidistant from all points on the circle.
   
   
   
   
   
   
 
   
(b)   A sector is the region enclosed by two radii and an arc.
   
   
   
   
   

 
(c)    An arc is a part of the circumference of a circle.

   
   
(d)   A segment is an area enclosed by an arc and a chord.