Kepler's Laws

gistfile1.txt

print ("This program will find Mass(kg), Radius(m) or Time(s) via Kepler's law's")
print ("Enter x for the unknown value")
m = (input("Mass: "))  
r = (input("Radius: "))
t = (input("Time: "))
x = ("unknown")
if m == x:
    m = ((4*3.14*r**3)/(.0000000000667*t**2))
    print ("m=")
elif r == x:
    r = ((t**2*.0000000000667*m)/(4*3.14*r**2))**(1/3)
    print ("r=")
elif t == x:
    t = ((4*3.14**2*r**3)/(.0000000000667*m))**(.5)
    print ("t=")