The diagram shows a circle of diameter D and a rectangle. Without using trigonometry, what is the length of the line A?
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Update and solution
Steve, who has some experience with mathematics, was the first to solve this one. Obviously this was a trick question, because the answer should have been staring readers in the face. See the diagram. No additional explanation will be provided.
The inspiration for this Quiz Question came from another Martin Gardner Book of Mathematical Problems and Diversions. This is the first edition. Last week’s Quiz Question came from the second edition. The problem is on page 111.
The idea is to make the problem appear hard when it is not. Apparently I am not able to fool all the people all the time.