# -*- coding: utf-8 -*-
In [1]: l = 4
In [2]: v = l**3
In [3]: v
Out [3]: 64



In [1]: import numpy as np
In [2]: r = 2
In [3]: a = np.pi*r**2
In [4]: c = 2*np.pi*r
In [5]: a
Out [5]: 12.566370614359172
In [6]: c
Out [6]: 12.566370614359172