Math CentralQuandaries & Queries


Question from Dian:

Okay, here is my problem. I have a 21" square and want to make it into an octagon. I am 61 and mathematically challenged. What I need to know is how many inches to each angle? I want this to be accurate as I am using it for a pattern.
Thanks so much!


We answered a similar question for Freddie recently but his square was 48 inches on a side. Using the same method the length y of the piece to cut off is 21/(√2 + 2) = 6.15 inches which is approximately 6 1/8 inches.


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