Problem:
A white cylindrical silo has a diameter of feet and a height of feet. A red stripe with a horizontal width of feet is painted on the silo, as shown, making two complete revolutions around it. What is the area of the stripe in square feet?
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Solution:
If the stripe were cut from the silo and spread at, it would form a parallelogram feet wide and feet high. So the area of the stripe is square feet.
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The problems on this page are the property of the MAA's American Mathematics Competitions