matrix dimensions of an oval (pretty basic question)

Hi everyone, I know this is a basic question, but I'm not sure how to determine the matrix dimensions of an oval. This is the code for my oval:

disc1 = [X-80,Y-80,X+80,Y+80] + repmat([rx, by], ?, ?)

the question marks represent the matrix dimensions for the [X-80,Y-80,X+80,Y+80] part, but I'm not sure how to determine what they are.

Any help would be must appreciated, thanks, Brett

[Brett]

Nevermind, 1,2 matrix dimensions seems to do the trick. :)