/* Horizontal Cylindrical Tank
A = pi*r^2/2 - r^2*arcsin(1-h/r) - (r-h)*sqrt(h(2r-h))
V = A * L
*/

function hcalc_cap(tankdims)
	{
	if (tgleL=='on'){
		var x=tankdims.length_zip.value;}
	else{ 
		var x=((tankdims.length_zip.value)/12);}
	if (tgleD=='on'){		
		var d=tankdims.diameter_zip.value;}
	else{
		var d=((tankdims.diameter_zip.value)/12);}

	var r=d/2;
	var total=((Math.pow(r,2))*(Math.PI)*x);
		tankdims.vol.value=(Math.round(total*100)/100) + " cubic feet";
		tankdims.gal.value=(Math.round(total*7.48051948*10)/10) + " gallons(US)";
	}

function hcalc_fill(tankdims)
	{
	if (tgleL=='on'){
		var x=tankdims.length_zip.value;}
	else{ 
		var x=((tankdims.length_zip.value)/12);}
	if (tgleD=='on'){		
		var d=tankdims.diameter_zip.value;}
	else{
		var d=((tankdims.diameter_zip.value)/12);}
	if (tgleH=='on'){		
		var h=tankdims.level_zip.value;}
	else{
		var h=((tankdims.level_zip.value)/12);}

	var r=d/2;
	var a1=(  (Math.PI)  *  (Math.pow(r,2))  /  2);
	var a2=(  (Math.pow(r,2))  *  (Math.asin(1-(h/r))));
	var a3=(  (r-h) * (Math.sqrt(h*((2*r)-h)))  );
	var A=(a1-a2-a3);
	var total=(A*x);
	if (isNaN(total))
		{total = 0;}
		tankdims.vol.value=(Math.round(total*100)/100) + " cubic feet";
		tankdims.gal.value=(Math.round(total*7.48051948*10)/10) + " gallons(US)";
	}



/* Spherical Tank 
     V = pi h^2 (R - h/3)
*/

function scalc_cap(tankdims)
	{
	if (tgleD=='on'){		
		var d=tankdims.diameter_zip.value;}
	else{
		var d=((tankdims.diameter_zip.value)/12);}

	var r=d/2;
	var total=((4/3)*(Math.PI)*(Math.pow(r,3)));
		tankdims.vol.value=(Math.round(total*100)/100) + " cubic feet";
		tankdims.gal.value=(Math.round(total*7.48051948*10)/10) + " gallons(US)";
	}

function scalc_fill(tankdims)
	{
	if (tgleD=='on'){		
		var d=tankdims.diameter_zip.value;}
	else{
		var d=((tankdims.diameter_zip.value)/12);}
	if (tgleH=='on'){		
		var h=tankdims.level_zip.value;}
	else{
		var h=((tankdims.level_zip.value)/12);}

	var r=d/2;
	var total=(((Math.PI)*(Math.pow(h,2)))*((r)-(h/3)));
	if (isNaN(total))
		{total = 0;}
			tankdims.vol.value=(Math.round(total*100)/100) + " cubic feet";
			tankdims.gal.value=(Math.round(total*7.48051948*10)/10) + " gallons(US)";
	}



/* Vertical Cylindrical Tank
A = pi*r^2
V = A * L
*/

function vcalc_cap(tankdims)
	{
	if (tgleL=='on'){
		var y=tankdims.length_zip.value;}
	else{ 
		var y=((tankdims.length_zip.value)/12);}
	if (tgleD=='on'){		
		var d=tankdims.diameter_zip.value;}
	else{
		var d=((tankdims.diameter_zip.value)/12);}

	var r=d/2;
	var total=(  (Math.PI) * (Math.pow(r,2)) * y);
		tankdims.vol.value=(Math.round(total*100)/100) + " cubic feet";
		tankdims.gal.value=(Math.round(total*7.48051948*10)/10) + " gallons(US)";
	}

function vcalc_fill(tankdims)
	{
	if (tgleD=='on'){		
		var d=tankdims.diameter_zip.value;}
	else{
		var d=((tankdims.diameter_zip.value)/12);}
	if (tgleH=='on'){		
		var h=tankdims.level_zip.value;}
	else{
		var h=((tankdims.level_zip.value)/12);}

	var r=d/2;
	var A=(  (Math.PI)  *  (Math.pow(r,2))  );
	var total=(A*h);
	if (isNaN(total))
		{total = 0;}
		tankdims.vol.value=(Math.round(total*100)/100) + " cubic feet";
		tankdims.gal.value=(Math.round(total*7.48051948*10)/10) + " gallons(US)";
	}