PI = 3.14

def main():
	"""
	Calcualates the area of a circle based on the user-specified radius
	"""

	# get the radius
	radius = float(input("Please enter the radius: "))

	# calculate the area of the circle
	area = calc_area(radius)

	# show area
	print("The area of a circle with radius %.4f is %.4f" % (radius, area))


def calc_area(radius):
	"""
	Calculates the area of a circle based on the given radius
	"""
	# calculate the area of a circle based with pi * r^2
	area = PI * radius ** 2

	return area


main()