1. Square Roots & Cube Roots
Unit 4

2. Square Roots
Squaring is the function used when we multiply a number by itself. 
We use the term square root for the number that was used to make the square. 
The radical sign (Ö) is used to represent square root.

3. What are PERFECT SQUARES?
How many squares are there?
1 x 1
A = 1 unit2
2 x 2
A = 4 units2
3 x 3
A = 9
To find the side length of any square, you need to find the square root of the area.

4. What is the root of each of these PERFECT SQUARES?
What would the square root of this number be? How would you guess? 16 4
144 12 64 8 72 72
N/A
169 13
The square root of a perfect square is just it’s base.

5. HINT: Take a look at the perfect squares that are close to 72.
How would you estimate the square root of a number?
Lets take a look 72
N/A
HINT: Take a look at the perfect squares that are close to 72. 10 20 30 40 50 60 70 80 90
100
110
120 64 81

6. Now all that’s left is an educated guess:10 20 30 40 50 60 70 80 90
100
110
120 64 81
So, your answer will be between 8 and 9, but a bit closer to 8.
72 is between 64 and 81, but is closer to 64.

7. Try These: 10 20 30 40 50 60 70 80 90
100
110
120

8. !