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

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

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

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

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

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

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