Question 1181168
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1. The diagonal of a square is the side length times the square root of 2, which is about 1.414.  Since the problem says the diagonal of the window is "about" 2.8m, the side length of the window is about 2.8/1.4 = 2m.  So you need about 2*2=4 square meters of plastic cover.<br>
2. The problem is not defined well enough.  There are an infinite number of ways you could cut a pizza in the shape of an equilateral triangle into two pieces of equal area with a single straight cut.<br>