how do i write this equation...

Question

circle with center (1,-3) that passes through the point (4,2).

I have (x-1)^2 + (y+3)^2=? how do i get the radius...

Answer 1

complete your equation to
(x-1)^2 + (y+3)^2= r^2

but (4,2) lies on your circle, so ...
(4-1)^2 + (2+3)^2 = r^2

etc.

Answer 2

thanks:)