SOLUTION: I'm supposed to find the standard form of the equation of a circle. The question is center at the origin containing the point: (-2,3). I have no idea where to begin. I've been work

Click here to see ALL problems on Circles

Question 510115: I'm supposed to find the standard form of the equation of a circle. The question is center at the origin containing the point: (-2,3). I have no idea where to begin. I've been working on this problem for about 2 hours. That answer in the back of the book is x^2+y^2=13.
Found 2 solutions by scott8148, Earlsdon:
Answer by scott8148(6628) (Show Source):
You can put this solution on YOUR website!
the general equation of a circle is ___ (x - h)^2 + (y - k)^2 = r^2
___ this is a circle centered at (h,k) with a radius of r

the circle in this question is centered at the origin (0,0)

the radius is the distance from the origin to (-2,3)

using the distance formula ___ (-2 - 0)^2 + (3 - 0)^2 = r^2

Answer by Earlsdon(6294) (Show Source):
You can put this solution on YOUR website!
Start with the basic equation of a circle with center at (h,k) and radius, r.
The center is at the origin, so (h,k) = (0,0). Substitute this.
which can be simplified to...
Now to find you use the distance formula: in which you'll find the distance between the circle's center (0,0) and the point contained on the cirle (-2,3).

but this is just so you substitute...