Question

    Find the third proportional to 13 and

    39?
    A 117 Correct Answer Incorrect Answer
    B 208 Correct Answer Incorrect Answer
    C 126 Correct Answer Incorrect Answer
    D 192 Correct Answer Incorrect Answer

    Solution

    Third proportional = a : b :: b : c It can be written as = b2 = ac   Here, a : b : c = 13 : 39 : c => 39 × 39 = 13 × c => c = (39 × 39)/13 = 117

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