function GeoCalc(){
var Surface;
side = eval(document.triiso.side.value);
base = eval(document.triiso.base.value);

if((side > 0) && (base > 0)){

	Surface = FormatNumber((base/2) * Math.sqrt(Math.pow(side,2) - Math.pow((base/2),2)));
	
	if(Surface >= 100)
		resultSurface = "&#928; = 3.141592653589793<br />Surface<br />" + Surface + "  cm<sup>2</sup><br />" + FormatNumber(Surface/10000) + "  m<sup>2</sup><br />";
	else
		resultSurface = "&#928; = 3.141592653589793<br />Surface<br />" + Surface + "  cm<sup>2</sup><br />";
	
	document.getElementById("surface").innerHTML = resultSurface;
}

}