11-1

1
11-1 11-2 Squares and Square Roots
(pgs 470-477)

• Indicator N9 ? Solve problems using exponents
  and square roots

2

• To Square a number multiply the number by
  itself.
• Perfect Squares Squares whose side lengths
  (square roots) are rational numbers. (ex 1, 4,
  9, 16, 25.)
• Radical Sign v Symbol used to indicate the
  square root of a number.

3

• Remember Squaring and square rooting are inverse
  operations so they are located on the same
  calculator key (You just need to push the 2nd
  key to get to the square root) Press in the ,
  2nd, then x².
• 44 and (-4)(-4) both equal 16, so 16 has two
  square roots v16 is asking for the positive or
  principal root 4.
• -v16 is asking for the negative root -4
• v16 is asking for both 4 -4

4

• Find the square of 5
• 55 25
• What is 19 squared
• 192 361
• Find v36
• v36 6
• Find v 676
• v 676 26

5

• Using squares and square roots
• The formula for kinetic energy ½mv2
• If a 6kg ball is soaring through the air at 5m/s,
  what is its kinetic energy?
• ½ mv2
• ½ 6kg (5m/s)2
• ½ 6kg25m2/s2
• 75kgm2/s2

6
To Estimate (without a calculator)

• First- remember that the square root of a perfect
  square is a rational number.
• To find an estimate for the square root of a
  number that is not a perfect square
• Lets recall some of the perfect squares-
• 1, 4, 9, 16, 25, 36, 49, 64, 81, 100

7
Continue estimating

• For example Estimate v96 to the nearest whole
  number
• Think of your perfect squares
• 1, 4, 9, 16, 25, 36, 49, 64, 81, 100
• 96 falls between 81 and 100
• Which is it closer to?
• So, the best estimate for v96 is 10.

8
To estimate (with a calculator)

• Remember Press in the , 2nd, then x²
• You can be a little more precise here
• For example Use a calculator to find the value
  of v37 to the nearest tenth.
• 6.08276253 Rounds to

6.1
9
Assignment

• 11-1/ 472 473/ 12-28e,29-51
• 11-2/ 477/ 17-24, 29-32, 35-44