import math

class Sirkel:
    def __init__(self, radius):
        self._radius = radius

    def diameter(self):
        return self._radius * 2

    def omkrets(self):
        return self.diameter() * math.pi

    def areal(self):
        return self._radius ** 2 * math.pi

sirkel1 = Sirkel(200)
sirkel2 = Sirkel(10)
print(sirkel1.omkrets())
print(sirkel1.areal())
print(sirkel2.diameter())