circle.py

class Circle(object):
    classType = "circle"
    def __init__(self, name):
        self.name = name
        
    def setRadius(self, radius):
        self.radius = radius
        
    def getArea(self):
        return "%s is a %s and has an area: %s" % (self.name, self.classType,3.1416*self.radius**2)
        
    def getPerim(self):
        return "%s is a %s and has a perim: %s" % (self.name, self.classType,3.1416*self.radius*2)

figuras.py

from triangle import Triangle
from circle import Circle
from square import Square
        
tri = Triangle("myTriangle")
tri.setSides(5,4,3)
print(tri.getArea())
print(tri.getPerim())

circ = Circle("myCircle")
circ.setRadius(4)
print(circ.getArea())
print(circ.getPerim())

sq  = Square("mySquare")
sq.setSide(3)
print(sq.getArea())
print(sq.getPerim())

square.py

class Square(object):
    classType = "square"
    def __init__(self, name):
        self.name = name
        
    def setSide(self, side):
        self.side = side
        
    def getArea(self):
        return "%s is a %s and has an area: %s" % (self.name, self.classType,self.side**2)
        
    def getPerim(self):
        return "%s is a %s and has a perim: %s" % (self.name, self.classType,self.side*4)     

triangle.py

class Triangle(object):
    classType = "triangle"
    def __init__(self, name):
        self.name = name
        
    def setSides(self, side1, side2, side3):
        self.side1 = side1
        self.side2 = side2
        self.side3 = side3
        
    def getArea(self):
        return "%s is a %s and has an area: %s" % (self.name, self.classType,self.side1 * self.side2 / 2)
    
    def getPerim(self):
        return "%s is a %s and has a perim: %s" % (self.name, self.classType,self.side1 + self.side2 + self.side3)