Problem 7

Two $8\times 8$ standard chessboards of equal size are placed on top of each other, lining up perfectly. One of the chessboards is then rotated by 45 degrees. What is the area of the intersection of the black squares of both chessboards, if the area of a single chessboard square is 1? Give your answer as a decimal rounded to 4 decimal points.

To deter guessing without thinking, we ask that you also solve the following simple arithmetic problem before checking your answer:

What is seven plus eight, subtract two?

This problem was first solved on Wed 12th March at 4:44:24pm