A boat heading out to sea starts out at Point A, at a horizontal distance of 639
feet from a lighthouse/the shore. From that point, the boat's crew measures
the angle of elevation to the lighthouse's beacon-light from that point to be
11°. At some later time, the crew measures the angle of elevation from point
B to be 3°. Find the distance from point A to point B. Round your answer to
the nearest foot if necessary.