function calculate() {
	var a = document.getElementById("a").value;
    var b = document.getElementById("b").value;
	var c;
	if(a != "" && b != ""){
		a = parseFloat(a);
        b = parseFloat(b);
		c = Math.round(Math.sqrt(((a*a)+(b*b)))*100)/100;
		document.getElementById("c").innerHTML = "c: " + c;
	}
}