Mon 20 Dec, 2004 12:20 am
Hi, I have an interesting problem with which I need your help to solve.
I have a partial roll of rug padding and I need to know how many linear feet there are.
I know this will be approximate, but I can live with a reasonably-close estimate.
The thickness of the material is 7/16".
The diameter of the roll is 11".
The core (empty part) is 3.25".
The thickness from the outside of the roll to the outside of the core is 4".
The circumference of the roll is 34.25".
How many linear feet of rug padding do I have?
Looking at the end, there are two concentric circles.
The large circle has a diameter of 11", so its area is 95 square inches.
The small circle has a diameter of 3.25 inches, so its area is 8.3 square inches.
Therefore, the padding consists of 86.7 square inches.
Since it is 7/16" thick, it must be 86.7 / (7/16) = 198 inches = 16.5 feet long.
I think the easiest would be to calculate the volume of carpet in the roll and divide it by the cross section of the carpet. Don't worry about the missing with of the carpet, it cancels itself out.
Ahh, markr beat me to it.
Holy cow! I never even thought of looking at this as a "volume" problem!
Thanks for your prompt responses!
(unfortunately, I have two 9 x 12 rugs, and therefore need just shy of 18 linear feet of padding).