Find the equation of the circle given:

Question

the centre is (0,0) and the circle passes through G(2,3)

Answer 1

The equation of a circle with center

(h, k) and radius r is

(x-h)² + (y-k)² = r²

 

We have (h,k) = (0,0)

 

The radius will be the distance from

the center to a point on the circle..

r is the distance from (0,0) to (2,3)

 

r = √[(2-0)²+(3-0)²] = √13

 

(x-0)²+(y-0)² = (√13)²

x²+y² = 13