BMI Calculator with GUI

[wocosc]

Alright.. I have the basic interface of the Body Mass Index worked out. However, I dont know how to get the feet,inches, and weight to be be multiplied:

(w / (h * 12 + x) * (h * 12 + x)) * 703)

Here is my code for the BMI Calculator:

from graphics import *
from math import *
def main():
    win = GraphWin("BMI Calculator", 800, 600)
    win.setCoords(-2.0, -2.0, 11, 11.5)
    Text(Point(5,5), "Feet:").draw(win)
    Text(Point(5,3), "Inches:").draw(win)
    Text(Point(5,1), "Weight:").draw(win)
    h = Entry(Point(7,5), 5)
    h.setText("0")
    h.draw(win)
    x = Entry(Point(7,3), 5)
    x.setText("0")
    x.draw(win)
    w = Entry(Point(7,1), 5)
    w.setText("0")
    w.draw(win)

   # Create Function Box
    Text(Point(3, 0), "BMI").draw(win)
    stng = Entry(Point(4,0), 7)
    stng.setText("0")
    stng.draw(win)

    output = Entry(Point(4,1), "" )
    output.draw(win)
    button = Text(Point(1.5,2.0), "Convert")
    button.draw(win)
    Rectangle(Point(1,1.5), Point(2,2.5)).draw(win)

    ## wait for a mouse click
    win.getMouse()

    ## convert input
    h =  float(eval(h.getText()))
    x =  float(eval(x.getText()))
    w =  float(eval(w.getText()))
    
    
    


    ## display output and change button
    BMI
   

    ## wait for click and then quit
    win.getMouse()
    win.close()

    main()

So I guess I now prompt my question.. How can I get an output box that (using the calculation that I put above) "prints" the answer..