12.3 Estimating square roots

Estimating square roots

To estimate square roots which are not perfect squares without using a calculator, we need to know the perfect square numbers well. We will first put the number inside the square root sign in the middle of a number line, and then find the two closest perfect square numbers on its left and right hand side to make the best estimation.


  • 1.
    Estimate the values to two decimal places. Check the answers with a calculator.
  • 3.
    Alice has baked a square cake that has a top surface area of 335 cm2c{m^2}. She has a rectangular box that has a width of 20 cm and length of 27 cm.
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Estimating square roots

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