import math


def circles_intersection(x_a, y_a, r_a, x_b, y_b, r_b):
    """
    Returns the point of intersection of two circkes
    :param x_a: x coordinate of the center of first circle
    :param y_a: y coordinate of the center of first circle
    :param r_a: radius of first circle
    :param x_b: x coordinate of the center of second circle
    :param y_b: y coordinate of the center of second circle
    :param r_b: radius of second circle
    :return: Array of coordinates of one of the intersection points
    """
    k = x_a*x_a - x_b*x_b + y_a*y_a - y_b*y_b - r_a*r_a + r_b*r_b
    c = 0.5 * k / (y_a - y_b)
    m = (x_a - x_b) / (y_b - y_a)
    g = c - y_a

    aa = 1 + m*m
    bb = 2*m*g - 2*x_a
    cc = x_a*x_a + g*g - r_a*r_a
    xi = 0.5 * (-bb + math.sqrt(bb*bb - 4*aa*cc)) / aa
    yi = m*xi + c
    return [xi, yi]