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square roots.notebook
April 18, 2016
Square Roots and Perfect Square Roots
To find the square root of a number, you find
the value that, when multiplied by itself, is
equal to the given number
radical
√x
radicand
Perfect square: A square of a whole number
How many square roots does the number 9
have?
Think what
numbers squared
=9
3 3 =9
-3 -3 = 9
Every positive number has two square
roots : one is positive, one is negative.
square roots.notebook
April 18, 2016
The positive root is called the principal
square root!
The negative root is called the negative
square root! _
Both roots are written:
_+
Let's List our Perfect Squares up to 20 !
Root (x)
1
2
3
4
5
6
7
x2
Root (x)
8
9
10
11
12
13
14
x2
Root (x)
15
16
17
18
19
20
x2
225
256
289
324
361
400
square roots.notebook
April 18, 2016
Finding square roots of fractions
1
9
1
=
9
= 1
3
Take the square root of the numerator
Take the square root of the denominator
square roots.notebook
April 18, 2016
1
4
-
9
16
49
100
±
25
81
-
144
169
225
900
Evaluate each expression
4 81 + 7
(
___
144
16
____
4
36
)
225
___
9
square roots.notebook
April 18, 2016
Solving Equations Using Square Roots
Remember: x x = x2
.
2
x = 121
2
x = 36
x2 = 49
400