Two circles of equal radii 'r' cut orghogoanlly If their centres are `(-2 ,3)` and `(-5 ,-6)` then `r`=

Two circles of equal radius of 5 units have their centres at the origin and the point (2, -3). Equation of the common chord of these circles is

Two circles of equal radii cut each other at P and Q, so that the centre of one lies on the other.A straight line through P cuts the circle again at A and B.Prove that Delta QAB is equilateral triangle.

If two circles of the same radius r and centres at (-1,2) and (3,6) respectively cut orthogonally,then the value of r is

The radius of one circle is twice the radius of another circle whose centres are (2,0) (1,2) respectively cutting orghogoanlly.Then the radius of the first circle is

Two circles C _(1) and C _(2) with equal radii r are centered at (3,2) and (6,5) respectively. If C _(1) and C _(2) intersect orthogonally, then r is equal to.