A circle is a path of a point moving at the same distance from a fixed point. The fixed point is called the centre, the fixed distance is called the radius and the distance around the circle is called the circumference. A chord of a circle is a line segment joining any two points on the circumference. A diameter is a chord passing through the centre. A diameter is a double the size of a radius. Any diameter of a circle divides it into two semi-circles. Any portion of a circle is called an arc. For two-point P and Q on the circle, we get the arc PQ.