Find the equation of the circle with center at (-3, 1) and through the point (2, 13)

Question

jdoe0001 · Answer

once you have the center, you have  the (h,k) values for your circle, then all you'd need is the radius

anonymous · Answer

How would i find the radius?

jdoe0001 · Answer

http://www.ipracticemath.com/Content/imagesLM/Algebra/distance-formula1.png the distance formula, between 2 points, you do have 2 points here, will give you the diameter, half that is the radius

anonymous · Answer

So would the final equation be (x+3)2+(y-1)2=121 ?

jdoe0001 · Answer

yes, but I don't get 121 though

jdoe0001 · Answer

lemme recheck

jdoe0001 · Answer

(-3-2)  = 5
(1-13)  = 12

jdoe0001 · Answer

so, that makes it $\sqrt{25+144} $

anonymous · Answer

Ok i see where i went wrong, that makes it so the diameter would be 13 and the radius would be 6.5

jdoe0001 · Answer

(-3-2) = -5, but anyhow, (-5)^2 still is 25

jdoe0001 · Answer

so,the distance between those 2 points is "13", and the radius would be 13/2

so 

$ (x+3)^2+(y-1)^2=\pmatrix{\frac{13}{2}}^2 $

anonymous · Answer

okay thank you! now i understand it way better :)

jdoe0001 · Answer

yw