Subject: cylinders or shafts
Name: JIm Campbell
Question: The same way that you would find the area, in square inches, of the label on a soup can. Slice the label vertically and roll it out flat. You get a rectangle with height the height of the label and length the circumference of the can. The circumference of a circle is 2 pi times the radius, so the area of the label (surface area of the "shaft") is 2 pi times (the radius) times (the height). We usually write this 2 pi r h Cheers,Harley
