Take an ordinary piece of typing paper; its dimensions will be 8 1/2 inches by 11 inches. Label the four corners A, B, C and D, clockwise from the top left (so that the short sides of the paper are AB and CD).

Label the midpoint of AB as E and the midpoint of BC as F.

Now make straight line folds in the paper from A to F and from D to E.

Label the point at which these folds cross as G.

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Now, find the exact area of the four-sided region GFCD. (No calculator approximations will count!)

Courtesy of Mark Nielsen