问答题 A young man who heard he could have the amount of land he walked in a day started on the road as soon as the sun rose. After walking for 8 miles, he marked the land by digging a hole in the ground and started out to the left again. His plan was to make a square. He did the same after 8 miles, turning left again. He was only able to cover 2 miles because the sun was about to set. He gave up his plan to make a square and came straight back to the starting line. He had barely made it back to the starting point, when he died. He covered a distance of 28 miles and was to receive 40 square miles of land at last. Had he known the principle of figures and suppose that the furthest distance he can travel before the sun sets is 28 miles, he only needs to walk forming a figure whose perimeter is 28 miles and whose area is the largest.