#### Lesson 3-1 Ideas/Vocabulary

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Lesson 3-1 Ideas/Vocabulary

• Find square roots of perfect squares.
• perfect square
• square root
• radical sign
Reinforcement of TEKS 7.1 The student represents
and uses numbers in a variety of equivalent forms.
(C) Represent squares and square roots using
geometric models.
Find Square Roots
Find
indicates the positive square root of 81.
Answer:
Interactive Lab: Square Roots
Find
A. A.
A 4
B. B.
B 6
C. C.
C 8
0%
D
0%
C
0%
B
D. D.
D 16
A
0%
Find Square Roots
Find
indicates the negative square root of
Answer:
Find
A. A
A.
B.
B
C.
C
B.
D.
0%
0%
D.
D
0%
C
A
0%
B
C.
D
Find Square Roots
Find
indicates both the positive and negative square
roots of 1.44.
Answer: Since (1.2)2 = 1.44 and (–1.2)2 = 1.44,
= ±1.2, or 1.2 and –1.2.
Find
A. A.
A ±1.2
B. B.
B ±1.25
C. C.
C ±1.5
0%
D
0%
C
0%
B
D. D.
D ±1.75
A
0%
Use Square Roots to Solve an Equation
ALGEBRA Solve x2 = 225.
x2 = 225
Write the equation.
x =
Definition of square root
x = 15 and x = –15
Check 15 15 = 225 and
(–15) (–15) = 225
Answer: The equation has two solutions, 15 and –15.
ALGEBRA Solve x2 = 81.
A. –9
A. A
B. 9
D.
D
0%
0%
0%
0%
D
C
D. –8 and 8
C
C.
B
B
C. –9 and 9
A
B.
Use Square Roots to Solve
a Problem
MUSIC The art work on the square picture in a
compact disc case is approximately 14,161 mm2 in
area. Find the length of each side of the square.
Words
Area is equal to the square of the length of a side.
Variable
Let s represent the length of a side.
Equation
14,161 = s2
Use Square Roots to Solve
a Problem
14,161 = s2
=s
2nd
c
14161
ENTER
=
Write the equation.
Definition of square root
Use a calculator.
119 = s
Answer: The length of a side of a compact disc case is
about 119 millimeters since distance cannot be
negative.
ART A piece of art is a square picture that is
approximately 11,025 square inches in area. Find
the length of each side of the square picture.
A. A.
A 85 inches
B. B.
B 93 inches
D. D.
D 105 inches
0%
0%
D
0%
C
A
0%
B
C. C.
C 95 inches