var math = {
    1 : function() {
        var a = prompt("A: "), b = prompt("B: "), c = prompt("C: ")
        console.log (
            a == 0 && Math.sqrt(Math.pow(c, 2) - Math.pow(b, 2)) ||         b == 0 && Math.sqrt(Math.pow(c, 2) - Math.pow(a, 2)) ||
            c == 0 && Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2)) ||
            "error, invalid parameters"
        )
    }
}

while ("David is cooler than Grant") {
    math[parseInt(prompt(
        "1) Pythagorean Theorem\n" +
        "2) Other Thing To Determine"
    ))]()
}