New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    A circular field, which covers an area of 1386 square

    meters, is planned to be enclosed by a compound wall that rises to a height of 3 meters. The wall is designed to be thin, with its thickness considered negligible. Calculate the surface area of one side of this compound wall.
    A 246 sq. m Correct Answer Incorrect Answer
    B 420 sq. m Correct Answer Incorrect Answer
    C 396 sq. m Correct Answer Incorrect Answer
    D 450 sq. m Correct Answer Incorrect Answer
    E 231 sq. m Correct Answer Incorrect Answer

    Solution

    Let the radius of the circular field = 'r' metres Then, area of the field = π X r2 = (22/7) X r2 = 1386 So, r2 = 1386 X (7/22) = 441 So, r = √441 = 21 {Since, radius cannot be negative} Circumference of the circular field = 2 X (22/7) X 21 = 132 metres So, surface area of one side of the compound wall = 2πr X height = 132 X 3 = 396 m2

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