import math


def polygon_area(side_length, amount_of_sides):
    """
     area of a polygon of
    :param side_length: side_length of a side of the polygon
    :param amount_of_sides: Amount of sides the polygon has
    :return: the area of the polygon
    """
    angle = 180 / amount_of_sides
    return 0.25 * amount_of_sides * (side_length ** 2) * (math.cos(math.radians(angle)) / math.sin(math.radians(angle)))