1. Find the perpendicular distance between the two parallel lines: y=mx+a and y=mx+b in terms of a, b, and m.
   
   
2. Put a round table into a (right-angled) corner so that the table top touches both walls and the feet are firmly on the ground. If there is a point on the perimeter of the table which is 10 inches from one wall and 5 inches from the other, what is the diameter of the table?

Source: 1. Original, Ken's POTD 3/24/94 2. Internet newsgroup rec.puzzles, Ken's POTD 5/4/94