I am cutting a piece of carpet that is 9 feet x 9 feet and need to cut it into an octagon. How far do I cut from the corner of the square. thank you for any help.

Larry,

Look at what Stephen did for a similar question. He showed that the side length x and the width w of a regular octagon are related by x = 0.4142 w. You have a width of 9 feet but you probably want to convert it to inches for your measurement (9 feet = 12 × 9 = 108 inches). The amount you cut off each corner (y in Stephens diagram) is then y = (w - x)/2.

I hope this helps,
Harley

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