Find the centre and radius of each of the following circles :

(x + 5)2 + (y – 3)2 = 20


The general form of the equation of a circle is:


(x - h)2 + (y - k)2 = r2


Where, (h, k) is the centre of the circle.


r is the radius of the circle.


Comparing the given equation of circle with general form we get:


h = - 5 , k = 3, r2 = 20


centre = ( - 5, 3) and radius = √20 = 2√5 units.


Ans: centre = ( - 5, 3) and radius = 2√5 units.


2