Question

Find the equation of the circle with center at the origin that contains the point ( 12 , 9 ) (12,9).

Answer 1

Radius is the length of line from centre to (12,9)
Equation of circle: (x-12)+(y-9)=r^2
r=√12^2+9^2=√169
r^2=(√169)^2=169
hence, (x-12)+(y-9)=169