Respuesta :

9514 1404 393

Answer:

  11 and 12

Step-by-step explanation:

√123 ≈ 11.0905 lies between 11 and 12.

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Since you're familiar with your squares, you know ...

  11^2 = 121

  12^2 = 144

123 lies between 121 and 144, so √123 lies between 11 and 12.