Estimation

• What is the approximate square root of 36?

  6 (since 6^2 = 36)
• What is the approximate square root of 144?

  12 (since 12^2 = 144)
• What is the approximate square root of 81?

  9 (since 9^2 = 81)
• What is the approximate square root of 196?

  14 (since 14^2 = 196, but the closest perfect square is 15^2 = 225)
• What is the approximate square root of 225?

  15 (since 15^2 = 225)