Question

Write the equation of the circle with center (−3, 2) and (6, 4) a point on the circle.

Answer 1

Radius=sqrt(2^2+9^2)
r=9.22
equation
(x+3)^2+(y-2)^2=9.22^2
(x+3)^2+(y-2)^2=85

Answer 2

$(x-h)^2+(y-k)^2=r^2$
center is (h,k) and radius is r

so

given center=(-3,2)=(h,k)
$(x-(-3))^2+(y-2)^2=r^2$
$(x+3)^2+(y-2)^2=r^2$
find r^2
ok, (6,4) is a point
sub 6 for x and 4 for y and evaluate

$(6+3)^2+(4-2)^2=r^2$
$(9)^2+(2)^2=r^2$
$81+4=r^2$
$85=r^2$


the equation is
$(x+3)^2+(y-2)^2=85$