Find the equation of the circle with:

Centre (a, b) and radius .

Given that we need to find the equation of the circle with centre (a, b) and radius .



We know that the equation of the circle with centre (p, q) and radius ‘r’ is given by:


(x - p)2 + (y - q)2 = r2


Now we substitute the corresponding values in the equation:


(x - a)2 + (y - b)2 =


x2 - 2ax + a2 + y2 - 2by + b2 = a2 + b2


x2 + y2 - 2ax - 2by = 0


The equation of the circle is x2 + y2 - 2ax - 2by = 0.


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