Question 1166536

It is 90ft between bases (home to 1st, 1st to 2nd, etc.) so
the area is just one of these sides squared: {{{90ft*90ft = highlight(8100ft^2) }}}<br>

The precise length from home plate to 2nd base is  90ft*{{{sqrt(2)}}} or approximately 127ft 3in  

-----
Not sure where the 120ft came from, unless you are talking about an "unofficial" baseball diamond.

For a square with diagonal measure 120ft, the side length is 120/{{{sqrt(2)}}} = 84.853ft and the area of such square is 7200{{{ft^2}}}