import math
import random

def calculate_pi(num_samples):
    in_circle = 0
    
    for i in range(num_samples):
        x = random.uniform(0,1)
        y = random.uniform(0,1)
        
        # figure out the distance
        dist = math.sqrt(x*x + y*y)

        # see if it's inside the circle
        if dist <= 1:
            in_circle += 1 # same as in_circle = in_circle + 1
            
    # calculate pi based on how many are in the circle
    return 4 * in_circle/float(num_samples)