Create a Python program to find the square root of the sum of two numbers without using the sqrt() function.
Num1 = 4
Num2 = 9
# Python program
import math 

def square_root(a, b): 
    return math.sqrt(a*a + b*b)
  
Num1 = 4
Num2 = 9

print("Square root of the sum of two numbers:", square_root(Num1, Num2))