Learn Class 11 Math - Circles

The circle is a location of a point that progresses at a regular distance from a fixed point. These fixed points are called the centre of the circle and this regular distance is called a Radius. If we consider r as the radius of the circle the diameter becomes d=2r.

Diameter is the maximal distance between any of the two points given in a particular circle.

Hence we can split up the diameter into two parts first from any endpoint of a circle to the centre and second from the centre to another endpoint on the circle.

The word circle is the origin from Greek which means kirkos, hoop, or ring.

General Equation of Circle:-

x²+y²+2gx+2fy+c=0 is the general equation of a circle, in which g, f, c, are constants.

The middle point of the circle is (-g, -f) that is -½ coefficient of x and -½ coefficient of y.

If the radius of the circle is equal to r then r=

If the radius r of the given circle x²+y²+2gx+2fy+c=0 touches the x and y-axis then g²=c and f²=c respectively.

Angle delimited at a centre of a circle by an arc given by arc/radius.