import math


def polar2cart(r, x0, y0, theta):
    """Changes polar coordinates to cartesian coordinate system.

    :param r: Radius
    :param x0: x coordinate of the origin
    :param y0: y coordinate of the origin
    :param theta: Angle
    :return: Cartesian coordinates
    :rtype: tuple (int, int)
    """
    x = int(x0 + r * math.cos(theta))
    y = int(y0 + r * math.sin(theta))
    return x, y