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Square Root and Cube Root Questions Answers

  • 15. Evaluate
    \begin{aligned} \sqrt[3]{4\frac{12}{125}} \end{aligned}

    1. \begin{aligned} 1\frac{2}{5} \end{aligned}
    2. \begin{aligned} 1\frac{3}{5} \end{aligned}
    3. \begin{aligned} 1\frac{4}{5} \end{aligned}
    4. 1
    Answer And Explanation

    Answer: Option B

    Explanation:

    \begin{aligned}
    = \sqrt[3]{\frac{512}{125}} \end{aligned}
    \begin{aligned}
    = (\frac{8*8*8}{5*5*5})^{\frac{1}{3}} \end{aligned}

    \begin{aligned} = \frac{8}{5} = 1\frac{3}{5} \end{aligned}

  • 16. Evaluate \begin{aligned} \sqrt[3]{\sqrt{.000064}} \end{aligned}

    1. 0.0002
    2. 0.002
    3. 0.02
    4. 0.2
    Answer And Explanation

    Answer: Option D

    Explanation:

    \begin{aligned} = \sqrt{.000064} \end{aligned}
    \begin{aligned} = \sqrt{\frac{64}{10^6}} \end{aligned}
    \begin{aligned} = \frac{8}{10^3} = .008 \end{aligned}
    \begin{aligned} = \sqrt[3]{.008} \end{aligned}
    \begin{aligned} = \sqrt[3]{\frac{8}{1000}} \end{aligned}
    \begin{aligned} = \frac{2}{10} = 0.2 \end{aligned}

  • 17. The largest four digit number which is a perfect cube, is:

    1. 7000
    2. 8000
    3. 9261
    4. 9999
    Answer And Explanation

    Answer: Option C

    Explanation:

    21*21*21 = 9261

  • 18. What is the smallest number by which 3600 be divided to make it a perfect cube.

    1. 450
    2. 445
    3. 440
    4. 430
    Answer And Explanation

    Answer: Option A

    Explanation:

    \begin{aligned}
    3600 = 2^3 \times 5^2 \times 3^2 \times 2
    \end{aligned}
    To make it a perfect cube it must be divided by
    \begin{aligned}
    5^2 \times 3^2 \times 2 = 450
    \end{aligned}

  • 19. The cube root of .000216 is

    1. 0.6
    2. 0.006
    3. 0.06
    4. .0006
    Answer And Explanation

    Answer: Option C

  • 20. \begin{aligned} \sqrt{\frac{32.4}{x}} = 2 \end{aligned}

    1. 8
    2. 8.1
    3. 9
    4. 9.1
    Answer And Explanation

    Answer: Option B

  • 21. \begin{aligned} \sqrt{\frac{0.081 * 0.484 }{0.0064 * 6.25}} \end{aligned}

    1. 0.66
    2. 0.77
    3. 0.88
    4. 0.99
    Answer And Explanation

    Answer: Option D