How to evenly distribute squares in a rectangular area?

Hi i need to figure out how can i add given number of squares in a rectangle i want to create this. http://i.stack.imgur.com/MHoda.jpg

The whole scenario is to create a function that take a number and then create a layout of it, for a quick reference i did this with predefined values for rows, columns, x&y scale etc. The size of the rectangle is fixed and it will always be something predefined, everything else need to be calculated with these values. Can anybody help me please??

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The first step is to figure out how many rows $R$ and columns $C$ you want. If you want N squares, you need $R*C\ge N$. If you are given the dimensions of the rectangle, say w is the ratio of the width $W$ to the height $H$(presumed $\ge 1$). Then you probably want $C/R$ to be about this, so $R^2w \ge N$ Now you can round up to get $R$ and divide and round up to get $C$.
To get the coordinates of each square of side $s$, there is some space $t$ between the squares. So $Cs+(C-1)t\le W$ and $Rs+(R-1)t\le H$ and you lay them out starting at (0,0) if that is top left in increments of $s+t$