from math import cos, sin, sqrt, pi

def distance(r,theta,z):
    
    x = r*cos(theta)
    
    y = r*sin(theta)
    
    d = sqrt(x**2 + y**2 + z**2)
    
    return d
    
dist = distance(3.0, 3*pi/4, 10.0)

print(dist)