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Carla, This question is asking whether we should use vectors, to which my answer is NO. You can assume without loss of generality that the roof is a pyramid with a square base. Because of the equal angles, the sides of the base each equal twice the height. Following Steve's notation, call the top of the pyramid A, the center of the square base X, and one of the corners of the square base Q. Then AX = 1, XQ = √2, and hence the measure of angle AQX is arctan (1/√2). Chris
 


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