1. Warm Up
Simplify. 25 64
144
225
5. 202
400

2. Squares and Square Roots
Lesson 3-5
Squares and Square Roots
You'll Learn how to
Find Square Roots

3. Perfect Squares 12 = 1 22 = 4 32 = 9 42 = 16 52 = 25 62 = 36 72 = 49
82 = 64
92 = 81
102 =
100
112 =
121
122 =
144
132 =
169
142 =
196
152 =
225
162 =
256
172 =
289
182 =
324
192 =
361
202 =
400

4. 25 1 Square root 5●5 Find Square roots
... a value that can be multiplied by itself to give the original number.
5●5 25
Perfect Square
Square Root
-5●-5
EXAMPLE 1
Find the two square roots of every number 10 ● 10 =
100 + – 1)
100 10
WHY?
(-10) ●
(-10) =
100 + – 2) 16 4

5. Simplify each expression
Principal Square root (Radical)
, is used to indicate the positive square root only.
EXAMPLE 2
Simplify each expression 1)
121 = 11 2)
5 + 11 = 16 = 4 25 16 5 3) = 4 3 ● 6
+ 7 18
+ 7 25 4) = = = 5) 36 49 6 ● 7 42 = =

6. Lesson Quiz
Find the two square roots of each number.
Evaluate each expression.
– 2 49 9
50 13 7
5. Ms. Estefan wants to put a fence around 3 sides of a square garden that has an area of 225 ft2. How much fencing does she need?
45 ft

7. Lesson Quiz for Student Response Systems
1. Find two square roots of each number. 64
A. 4
B. 8
C. 9
D. 16 7

8. Lesson Quiz for Student Response Systems
2. Find two square roots of each number.
6400
A. 4
B. 8
C. 80
D. 800 8

9. Lesson Quiz for Student Response Systems
3. Evaluate the expression.
A. 17
B. 17
C. 19
D. 72 9

10. Lesson Quiz for Student Response Systems
4. Evaluate the expression.
A. 4
B. 8
C. 16
D. 40 10