Brain Fart: Equation of a circle

[MolecularMan14]

Im sorry everyone, but I just had a brain fart and I cant seem to find this anywhere, so what is the equation for a circle? Basically, if I had an equation like x(squared) + y(squared) = 10x-8y+6 what would the center and the radius of that circle be? Im very confused at this point, because Im not a big fan of geometry, but any and all help is appreciated

Thanks,

Alex

[ydoaPs]

[math](x-h)^2+(y-k)^2=r^2[/math] (h,k) is the centre and r is the vertex.

[mezarashi]

When you get a problem like that where the equation is as you mentioned:

 

x(squared) + y(squared) = 10x-8y+6

 

The strategy is basically to factor the x and y so that it takes the form of the equation mentioned by yourdadonapogos. Once the equation is of that form, then information like it's center and radius are only but obvious

[Ducky Havok]

I've always heard r referred to as the radius, not the vertex. Are they the same thing essentially?

[Dave]

I've never really heard the term vertex used in relation to a circle either. I suspect a mistype.

[Severian]

He probably means that r is the vector from the centre to a point on the circle.

[ydoaPs]

no, i was just typing fast and had a wierd day. i meant radius. sorry for the confusion.