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CEMC Gauss (Grade 8), 1999

Geometry Difficulty 2.0 Junior Find the answer Canada

Four identical isosceles triangles border a square of side $6$ cm, as shown. When the four triangles are folded up they meet at a point to form a pyramid with a square base. If the height of this pyramid is $4$ cm, the total area of the four triangles and the square is

(A) $84\text{ cm}^2$ (B) $98\text{ cm}^2$ (C) $96\text{ cm}^2$ (D) $108\text{ cm}^2$ (E) $90\text{ cm}^2$

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