Download Find Square Roots Find

Main Idea and New Vocabulary
Key Concept: Square Root
Example 1: Find Square Roots
Example 2: Find Square Roots
Example 3: Find Square Roots
Example 4: Find Square Roots
Example 5: Use Square Roots to Solve an Equation
Example 6: Real-World Example
• Find square roots of perfect squares.
• perfect square
• square root
• radical sign
Find Square Roots
Find
.
Find the positive square root of 81;
92 = 81.
Answer: 9
Find
.
A. 5
B. 10
C. –10 or 10
D. no real square root
Find Square Roots
Find
.
Find both square roots of 1.44;
1.22 = 1.44.
Answer: 1.2
Find
A. 6
B. 0.6
C. 0.6
D.
0.06
.
Find Square Roots
Find
.
Find the negative square root of
Answer:
Find
.
A.
B.
C.
D. no real square root
Find Square Roots
Find
.
Answer: There is no real square root because no
number times itself is equal to –49.
Find
.
A. –11
B. 11 or –11
C. –1.1
D. no real square root
Use Square Roots to Solve an
Equation
ALGEBRA Solve x2 = 225.
x2 = 225
Write the equation.
x=
Definition of square root
x = 15 and –15
Check 15 • 15 = 225
and (–15)(–15) = 225 
Answer: The equation has two solutions,
15 and –15.
ALGEBRA Solve n2 = 400.
A. 20
B. 20 and –20
C. 40 and –40
D. no real square root
PUZZLE A square puzzle has an area of
35,721 square millimeters. What is the length
of a side of the square?
s2 = 35,721
Write the equation.
Definition of square root
To find
, find two equal factors of 35,721.
35,721 = 3 • 3 • 3 • 3 • 3 • 3 • 7 • 7
Find the prime factors.
= (3 • 3 • 3 • 7)(3 • 3 • 3 • 7)
Regroup into two
equal factors.
So, s = 3 • 3 • 3 • 7 or 189.
Answer: Since distance cannot be negative, the
length of each side is 189 millimeters.
MAZES A square corn maze has an area of
12,996 square feet. What is the length of a side of
the square?
A. 57 ft
B. 114 ft
C. 228 ft
D. 6,498 ft