Common Square Roots

Updated January 31, 2023 | Logan Chamberlain

What are square roots and why do we care?

The square root of a number is a number that, when multiplied by itself, equals the desired value. So, for example, the square root of 49 is 7 (7x7=49). The process of multiplying a number times itself is called squaring.

Numbers whose square roots are whole numbers, (or more accurately positive integers) are called perfect square numbers. Numbers with decimals aren't perfect square roots.

All positive numbers will have a positive number as their square root, called the principal, and a negative number. These numbers are all known as real numbers.

All negative numbers will have a complex number as their square root. A complex number is a number multiplied by i. i is the "imaginary" square root of -1. It's called imaginary, but it does exist to mathematicians.

How do we write out square roots?

A square root equation is written out using a radical sign or radical symbol (√). The number that we want to get the root of comes after or under the tail of the radical (for example √3 if we wanted to find the square root of 3). The number after the radical is called the radicand. On a calculator, instead of the radical, you might see "sqrt".

What do we use square roots for?

It may be a bit hard to picture it, but square roots are some of the most useful numbers around. Square root functions are super important for physics equations of all kinds. They're also valuable for statistics; statisticians use square roots all the time in analyzing the correlation between different points of data.

List of Perfect Squares

Use this table to find the squares and square roots of numbers from 1 to 100.

You can also use this table to estimate the square roots of larger numbers.

  • For instance, if you want to find the square root of 2000, look in the middle column until you find the number that is closest to 2000. The number in the middle column that is closest to 2000 is 2,025.
  • Now look in at the number to the left of 2,025 to find its square root. The square root of 2,025 is 45.
  • Therefore, the approximate square root of 2,000 is 45.

To get a more exact number, you will have to use a calculator (44.721 is the more exact square root of 2,000).

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NUMBER SQUARE SQUARE ROOT
1 1 1.000
2 4 1.414
3 9 1.732
4 16 2.000
5 25 2.236
6 36 2.449
7 49 2.646
8 64 2.828
9 81 3.000
10 100 3.162
11 121 3.317
12 144 3.464
13 169 3.606
14 196 3.742
15 225 3.873
16 256 4.000
17 289 4.123
18 324 4.243
19 361 4.359
20 400 4.472
21 441 4.583
22 484 4.690
23 529 4.796
24 576 4.899
25 625 5.000
26 676 5.099
27 729 5.196
28 784 5.292
29 841 5.385
30 900 5.477
31 961 5.568
32 1,024 5.657
33 1,089 5.745
34 1,156 5.831
35 1,225 5.916
36 1,296 6.000
37 1,369 6.083
38 1,444 6.164
39 1,521 6.245
40 1,600 6.325
41 1,681 6.403
42 1,764 6.481
43 1,849 6.557
44 1,936 6.633
45 2,025 6.708
46 2,116 6.782
47 2,209 6.856
48 2,304 6.928
49 2,401 7.000
50 2,500 7.071
51 2,601 7.141
52 2,704 7.211
53 2,809 7.280
54 2,916 7.348
55 3,025 7.416
56 3,136 7.483
57 3,249 7.550
58 3,364 7.616
59 3,481 7.681
60 3,600 7.746
61 3,721 7.810
62 3,844 7.874
63 3,969 7.937
64 4,096 8.000
65 4,225 8.062
66 4,356 8.124
67 4,489 8.185
68 4,624 8.246
69 4,761 8.307
70 4,900 8.367
71 5,041 8.426
72 5,184 8.485
73 5,329 8.544
74 5,476 8.602
75 5,625 8.660
76 5,776 8.718
77 5,929 8.775
78 6,084 8.832
79 6,241 8.888
80 6,400 8.944
81 6,561 9.000
82 6,724 9.055
83 6,889 9.110
84 7,056 9.165
85 7,225 9.220
86 7,396 9.274
87 7,569 9.327
88 7,744 9.381
89 7,921 9.434
90 8,100 9.487
91 8,281 9.539
92 8,464 9.592
93 8,649 9.644
94 8,836 9.695
95 9,025 9.747
96 9,216 9.798
97 9,409 9.849
98 9,604 9.899
99 9,801 9.950
100 10,000 10.000
NOTE: Square roots in this table are rounded to the nearest thousandth.

 

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