u in the range [0, 1).D from the origin using the inverse CDF: D = sqrt(u).theta in the range [0, 2*PI).(D, theta) to Cartesian coordinates to get the point (x, y):
x = D * cos(theta)y = D * sin(theta)(x, y) by the circle's center (x_center, y_center):
x += x_centery += y_center(x, y) as the random point inside the circle.