Sat math Essentials

rad-
ical
. The number inside of the radical is called the 
radicand
.
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N U M B E R S A N D O P E R AT I O N S R E V I E W
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4 3

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36
6 because 6
2
36
36 is the square of 6, so 6 is the square root of 36.
Practice Question 
Which of the following is equivalent to 
196
?
a.
13
b.
14
c.
15
d.
16
e.
17
Answer
b.
196
14 because 14
14 
196.
Perfect Squares
The square root of a number might not be a whole number. For example, there is not a whole number that can
be multiplied by itself to equal 8.
8
2.8284271 . . . .
A whole number is a 
perfect square
if its square root is also a whole number:
1
is a perfect square because 
1
1
4
is a perfect square because 
4
2
9
is a perfect square because 
9
3
16
is a perfect square because 
16
4
25
is a perfect square because 
25
5
36
is a perfect square because 
36
6
49
is a perfect square because 
49
7
Practice Question
Which of the following is a perfect square?
a.
72
b.
78
c.
80
d.
81
e.
88
Answer
d.
Answer choices 
a
,
b
,
c
, and 
e
are incorrect because they are not perfect squares. The square root of a
perfect square is a whole number;
72
≈
8.485;
78
≈
8.832;
80
≈
8.944;
88
≈
9.381; 81 is a per-
fect square because 
81
9.