circle, chord , diameter, circumference, are of circle

 Circle

Definition of circle - Circle is the set (group) of all those points which are equidistant from a fixed point.

this fixed point is called the centre(O) of the circle.

circle

Radius of the circle- If we construct a line which join centre of the circle to the any point of boundary (circumference) of the circle. Generally we denote radius by r.

OA,OB. OC OD are radius of circle

Chord of a circle- Line joining the two points of a circle is called chord.

AB, CD, EF are chords 

Diameter of a circle- A line (chord) that passes through the centre of the circle is called diameter of circle.Diameter is the longest chord.

Relation between diameter and radius-

                diameter = 2 (radius) 

Area of circle 

 Area of circle = 𝞹r²    (where 𝞹 = 22/7 and r = radius)

Circumference of circle- length of the boundary of a circle or perimeter of  a circle is called circumference.

circumference of a circle = 2𝞹r  (where 𝞹 = 22/7 and r = radius)