function PTRamount(d){
			
		var WrkTable=document.getElementById("PTRamountText");
		WrkTable.style.visibility="visible";	
		
		var amountl = 0;
		
	   amountl = getAmount(d);
      
		WrkTable.value = "You Will Need  " + amountl +  "  Lbs. Of Glass " ;
	
	}
	
	function getAmount(d) {
		
		var amountl=0;
		var basel =0;

        dn = d - 0;

		basel = (dn * dn * 2) / 231;
		basel = basel * .8;
		amountl = (Math.round((basel * 12) * 1.25));
		return amountl;
	}