Khalif is cleaning his room and kicks a hat off the floor to the top of a bookshelf. If he is standing 5 feet from the shelf and he kicks the hat 18 feet, how tall is the shelf? Round to the nearest tenth if necessary.

Adrawer contains 12 identical white socks, 18 identical black socks and 14 identical brown socks. what is the least number of socks you must choose, without looking, to be certain that you have chosen two socks of the same colour?