pgm7a.py

import math

class Shape:
    def __init__(self):
        self.area = 0
        self.name = ""

    def showArea(self):
        print("The area of the", self.name, "is", self.area, "units")

class Circle(Shape):
    def __init__(self, radius):
        super().__init__()
        self.name = "Circle"
        self.radius = radius

    def calcArea(self):
        self.area = math.pi * self.radius * self.radius

class Rectangle(Shape):
    def __init__(self, length, breadth):
        super().__init__()
        self.name = "Rectangle"
        self.length = length
        self.breadth = breadth

    def calcArea(self):
        self.area = self.length * self.breadth

class Triangle(Shape):
    def __init__(self, base, height):
        super().__init__()
        self.name = "Triangle"
        self.base = base
        self.height = height

    def calcArea(self):
        self.area = self.base * self.height / 2

c1 = Circle(5)
c1.calcArea()
c1.showArea()

r1 = Rectangle(5, 4)
r1.calcArea()
r1.showArea()

t1 = Triangle(3, 4)
t1.calcArea()
t1.showArea()