Calculates the rolled length of a roll of material when the outside diameter of the material, thickness of the material, and the diameter of the hole in the center or the tube on which the material is wound are given. Variations due to stretching or softness of the material are to be ignored. An example of rolled material would be a rolled carpet or a rolled sheet of paper from the paper mill. The length units that can be used are yard, feet, inch, meter, centimeter, millimeter, mil, and micron. A mil is equal to one thousandth of an inch. A micron is equal to one thousandth of a millimeter. The initial units used in the table can be changed to any of the choices given.