Show that the equation `x^2+y^2-6x+8y+21=0` represents a circle.Find the centre and radius of the circle.

Does each of the following equation represent a circle? If so, find the centre and radius of the circle. (iii) 2x ^2 + y ^2 - 6x -8y - 11 = 0

Does each of the following equation represent a circle? If so, find the centre and radius of the circle. (ii) x ^2 + y ^2 - 4x + 5 = 0

Does each of the following equation represent a circle? If so, find the centre and radius of the circle. (i) x ^2 + y ^2 + 2x + 4y - 45 = 0

Find the centre and radius of the circle x^2+y^2+8x+10y-8=0 .

the equation x^2 + y^2 = 0 does not represent any locus - Give reasons.

The roots of the equation x+2y=4 and 2x-y=0 are

The roots of the equation x+2y=4 and 2y-x=0 are

Determine the centre and the radius if the circle x^2+y^2-8x+10y-12=0

Find the equation of a circle whose centre is (1,2) and radius 2.

The angle at the center of a sector of a circle is 60^@ and the radius of the circle is 21 cm.Find the perimeter and the area of the sector of the circle.