Question

    The ratio of the curved surface area to the total

    surface area of a cone is 5:9. Determine the ratio of the radius of the cone to its slant height. (Use π = 22/7)
    A 3:5 Correct Answer Incorrect Answer
    B 5:6 Correct Answer Incorrect Answer
    C 5:7 Correct Answer Incorrect Answer
    D 4:5 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Curved surface area of cone = πRL, where 'R' is radius and 'L' is slant height Total surface area of cone = πR(R + L) , where 'R' is radius and 'L' is slant height So, [πRL]:[πR(R + L) ] = 5:9 Or, L:(R + L) = 5:9 Or, 9L = 5R + 5L Or, 4L = 5R Or, R:L = 4:5

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