Math Brain Teaser: How to Choose a Mans Shirt

You have been invited to an important fundraising gala at your old college and decided that this black-tie event demands a short collar super white Italian shirt, like the one you bought years ago for your wedding. When you bravely tried the wedding shirt on (size 16), your wife noted that the collar suffocates you and you need about 1/4″ more space everywhere in-between your neck and the collar all around your neck. What size shirt do you need to buy?  In case you don’t know the shirt size 16 means that a tape wrapped around your neck and two fingers positioned flat upfront will measure 16 inches.

(Puz­zle answer is below. Please try to solve it before check­ing out the answer!)

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Puzzle answer
Yes, surprising use of math in the dressing room to refresh our geometry. Shirt collar is almost circular, and circle circumference = 2 x Pi x Radius. The shirt size 16 means that a tape wrapped around your neck and two fingers positioned flat upfront will measure 16 inches.

At the time of your wedding: 2 x Pi x Radius of your neck = 16.
Now: 2 x Pi x new Radius of your neck = 2 x Pi x (wedding Radius of your neck + 1/4) = 2 x Pi x wedding Radius of your neck + 2 x Pi x 1/4 = 16 + Pi/2 = 16 + 3.14/2 = 17.57 (approx). So, you are more around size 17.5 now.

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