Find the equation of the circle if the chord of the circle joining (1, 2) and `(-3,1)` subtents `90^0` at the center of the circle.

Find the equation of the circle passing through the points (1,1), (2,-1), and (3,2).

Find the equation of the circle with centre (0,2) and radius 2

Find the equation of the circle on the line joining the points (-2,3) and (1,-2) as diameter.

Find the equation of the circle with centre at (-1,0) and radius 2.

Find the equation of the circle through the points (1 ,0), (-1,0) and (0,1)

Find the equation of the chord of the circle x^2+y^2=9 whose middle point is (1,-2)

Find the equation of the circle passing through the points (1,-2),(2,-1),(3,1) .

Find the equation of the circle with centre (1,1) and radius sqrt(2)

Find the equation of the circle with the line joining (2,3) and (-2,-1) as diameter. Find the equation of the tangent at the point (2,3) to this circle.