# David Powis-Dow CS 101:Python 
# 2016-12-03 v0.1
# Chapter 4 : Exercise - Sum_to fruitful function    

def area_of_circle(r):
    """
      Returns the area r of a circle. 
    """
    radius = r 
    return(float(radius)*float(radius)*3.14)

area_of_circle(3)

print(area_of_circle(3))





