Question

    On a rectangular wall of length 21 metres and height 18

    metres, there is a window in the shape of triangle surmounted on a square. If the base of triangle and square overlap and length of each side of the square is 4 metres and length of altitude of the triangle is 3 metres, then excluding the window, what is the surface area (in m2) of the wall?
    A 346 Correct Answer Incorrect Answer
    B 356 Correct Answer Incorrect Answer
    C 326 Correct Answer Incorrect Answer
    D 316 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Surface area of the entire wall = length × height = 21 × 18 = 378 m2 Surface area of the window = Sum of surface area of the square part + surface area of the triangular part = 42 + (1/2) × 4 × 3 = 16 + 6 = 22 m2 So, desired surface area = 378 – 22 = 356 m2

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