Finding and Estimating Square Roots

1
Finding and Estimating Square Roots

• ESL students

2
Square Root

• The inverse of the square of a number

3
Square Root

• Indicated by the symbol

Radical Sign and the expression under the radical
sign is a radicand.
4
The square root of a number is just a number
which when multiplied by itself gives you back
your original number.
So 2 is the square root of 4 because 2 x 2 4.
BUT . . . some numbers do not have a perfect
square root ?
How can we determine the square root of a number
that is NOT square?
5
Todays Sub-topics

• Simplifying Square Root Expressions
• Rational and Irrational Square Roots
• Estimating Square Roots
• Approximating Square Roots with a Calculator

6
Simplifying Square Root

• Simplify each expression
• 8 positive square root
• 21
• -0.2 negative square root
• 11 -11 positive negative square
  root

7
Rational and Irrational Square Roots

• Irrational Numbers
• It is a non-repeating, non-ending decimal.
• An irrational number can result from a square
  root of a non-perfect square.
• Other example of irrational numbers are things
  like

8
Identify each root as rational or irrational.
9
Estimating Square Roots
10
Estimating Square Roots

• It is very handy to know by heart some of the
  first few perfect square numbers.
• This will help you see patterns and have some
  idea if your calculated answers are close.

11

• Video
• Time

12
Approximating with a Calculator

• Find the square root of 14.52 to the nearest
  hundredth
• Find the square root of 17.81 to the nearest
  hundredth