4. {5\"} A lifeguard sits on a sand}: beadi directly facing the shoreline and sees a distressed swimmer out in the water to their left. Being a student of physics. the lifeguard realizes that the fastest path to the swimmer is not to run directly toward them since progress along the sand while running a, {sand} is much faster than progress in the water 1:\". [water] while swimming. Suppose that v, = n\". and that the swimmer is as far from the shoreline as the lifeguard is. The angle of the line of sight to the swimmer is 30 degrees to the left as viewed by the lifeguard. At what angle should thegl.r start running to arrive in the shortest amount of time? Use zero degrees as direuztl},r toward the shoreline