What are those mysterious square roots that often confuse students and complicate their lives? The truth is that to understand them, we need to grasp the concept of the inverse operation.

What is a square root?

When we solve an exercise like 5=252 5=25^2 , it's clear that 5 5 times 5 5 (that is, multiplying the number by itself) results in 25 25 . This is the concept of a power, or to be more precise, a square power, which to apply, we must multiply the figure or the number by itself.

The concept of "square root" refers to the inverse operation of squaring numbers.

That is, if we have X2=25X^2=25 and we want to find the value of XX, what we need to do is perform an identical operation on both sides of the equation.

A - The concept of square root refers to the inverse operation of squaring numbers

This operation is the square root.

So, we have: X2=25\sqrt{X^2} = \sqrt{25} and the result is X=5 X=5 .

Suggested Topics to Practice in Advance

  1. Exponents and Roots - Basic
  2. Exponents and Exponent rules
  3. Basis of a power
  4. The exponent of a power
  5. Powers

Practice Square Roots

Examples with solutions for Square Roots

Exercise #1

Choose the largest value

Video Solution

Step-by-Step Solution

Let's begin by calculating the numerical value of each of the roots in the given options:

25=516=49=3 \sqrt{25}=5\\ \sqrt{16}=4\\ \sqrt{9}=3\\ We can determine that:

5>4>3>1 Therefore, the correct answer is option A

Answer

25 \sqrt{25}

Exercise #2

36= \sqrt{36}=

Video Solution

Step-by-Step Solution

Let's solve the problem step by step:

  • Step 1: Understand what the square root means.
  • The square root of a number nn is a value that, when multiplied by itself, equals nn. This is written as x=nx = \sqrt{n}.

  • Step 2: Apply this definition to the number 3636.
  • We are looking for a number xx such that x2=36x^2 = 36. This translates to finding x=36x = \sqrt{36}.

  • Step 3: Determine the correct number.
  • We know that 6×6=366 \times 6 = 36. Therefore, the principal square root of 3636 is 66.

Thus, the solution to the problem is 36=6 \sqrt{36} = 6 .

Among the given choices, the correct one is: Choice 1: 66.

Answer

6

Exercise #3

49= \sqrt{49}=

Video Solution

Step-by-Step Solution

To solve this problem, we follow these steps:

  • Step 1: Understand that finding the square root of a number means determining what number, when multiplied by itself, equals the original number.
  • Step 2: Identify the numbers that could potentially be the square root of 4949. These are ±7 \pm7, but by convention, the square root function typically refers to the non-negative root.
  • Step 3: Calculate 7×7=497 \times 7 = 49. This confirms that 49=7 \sqrt{49} = 7.
  • Step 4: Verify using the problem's multiple-choice answers to ensure 77 is among them, confirming choice number .

Therefore, the solution to the problem 49 \sqrt{49} is 7 7 .

Answer

7

Exercise #4

64= \sqrt{64}=

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Recognize what finding a square root means
  • Step 2: List known perfect squares to identify which one results in 64
  • Step 3: Verify the square root by calculation

Now, let's work through each step:
Step 1: To find the square root of 64, we seek a number that, when multiplied by itself, equals 64.
Step 2: Consider the sequence of perfect squares: 12=1 1^2 = 1 , 22=4 2^2 = 4 , 32=9 3^2 = 9 , 42=16 4^2 = 16 , 52=25 5^2 = 25 , 62=36 6^2 = 36 , 72=49 7^2 = 49 , 82=64 8^2 = 64 .
Step 3: We see that 82=64 8^2 = 64 . Therefore, the square root of 64 is 8.

Therefore, the solution to this problem is 8 8 .

Answer

8

Exercise #5

Solve the following exercise:

x2= \sqrt{x^2}=

Video Solution

Step-by-Step Solution

In order to simplify the given expression, we will use two laws of exponents:

a. The definition of root as an exponent:

an=a1n \sqrt[n]{a}=a^{\frac{1}{n}} b. The law of exponents for power of a power:

(am)n=amn (a^m)^n=a^{m\cdot n}

Let's start with converting the square root to an exponent using the law mentioned in a':

x2=(x2)12= \sqrt{x^2}= \\ \downarrow\\ (x^2)^{\frac{1}{2}}= We'll continue using the law of exponents mentioned in b' and perform the exponent operation on the term in parentheses:

(x2)12=x212x1=x (x^2)^{\frac{1}{2}}= \\ x^{2\cdot\frac{1}{2}}\\ x^1=\\ \boxed{x} Therefore, the correct answer is answer a'.

Answer

x x

Exercise #6

5+361= 5+\sqrt{36}-1=

Video Solution

Step-by-Step Solution

To solve the expression 5+361= 5+\sqrt{36}-1= , we need to follow the order of operations, often remembered by the acronym PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).


Here are the steps:


First, calculate the square root:

36=6 \sqrt{36} = 6

Substitute the square root back into the expression:

5+61 5 + 6 - 1

Next, perform the addition and subtraction from left to right:

Add 5 and 6:

5+6=11 5 + 6 = 11

Then subtract 1:

111=10 11 - 1 = 10

Finally, you obtain the solution:

10 10

Answer

10 10

Exercise #7

100= \sqrt{100}=

Video Solution

Step-by-Step Solution

The task is to find the square root of the number 100. The square root operation seeks a number which, when squared, equals the original number. For any positive integer, if x2=100 x^2 = 100 , then x x should be our answer.

Step 1: Recognize that 100 is a perfect square. This means there exists an integer x x such that x×x=100 x \times x = 100 . Generally, we recall basic squares such as:

  • 12=1 1^2 = 1
  • 22=4 2^2 = 4
  • 32=9 3^2 = 9
  • and so forth, up to 102 10^2

Step 2: Checking integers, we find that:

102=10×10=100 10^2 = 10 \times 10 = 100

Step 3: Confirm the result: Since 10×10=100 10 \times 10 = 100 , then 100=10 \sqrt{100} = 10 .

Step 4: Compare with answer choices. Given that one of the choices is 10, and 100=10 \sqrt{100} = 10 , choice 1 is correct.

Therefore, the square root of 100 is 10.

Answer

10

Exercise #8

121= \sqrt{121}=

Video Solution

Step-by-Step Solution

To solve the problem of finding the square root of 121, let's follow these steps:

  • Step 1: Understand that we need to find a number x x such that x2=121 x^2 = 121 .
  • Step 2: Recognize that 121 is a perfect square. Specifically, 11×11=121 11 \times 11 = 121 .
  • Step 3: Therefore, the square root of 121 is clearly 11 11 .

Thus, the solution to the problem is 11 11 .

Answer

11

Exercise #9

144= \sqrt{144}=

Video Solution

Step-by-Step Solution

To solve this problem, we proceed with the following steps:

  • Step 1: Identify that the problem asks for the square root of 144.
  • Step 2: Use the concept of square roots, where n=x\sqrt{n} = x implies x2=nx^2 = n.
  • Step 3: Check for a perfect square whose square equals 144.

Now, let's solve the problem:

Step 1: We need the square root 144\sqrt{144}.

Step 2: Recall that x2=144x^2 = 144. We need to find xx.

Step 3: Recognize that 144 is a perfect square and find xx such that x2=144x^2 = 144. Through either calculation or prior knowledge, we know:
122=14412^2 = 144.

Therefore, the square root of 144 is 144=12\sqrt{144} = 12.

Thus, the solution to the problem is 12\mathbf{12}.

Answer

12

Exercise #10

16= \sqrt{16}=

Video Solution

Step-by-Step Solution

To determine the square root of 16, follow these steps:

  • Identify that we are looking for the square root of 16, which is a number that, when multiplied by itself, equals 16.
  • Recall the basic property of perfect squares: 4×4=16 4 \times 4 = 16 .
  • Thus, the square root of 16 is 4.

Hence, the solution to the problem is the principal square root, which is 4 4 .

Answer

4

Exercise #11

225= \sqrt{225}=

Video Solution

Step-by-Step Solution

To solve the problem, we will follow these steps:

  • Step 1: Identify the perfect squares near 225.
  • Step 2: Calculate to find which integer when squared equals 225.

Now, let's work through the steps:

Step 1: The perfect squares around 225 are 196=142196 = 14^2, 225=152225 = 15^2, and 256=162256 = 16^2.
Step 2: We calculate 152=15×15=22515^2 = 15 \times 15 = 225, therefore, 225=15\sqrt{225} = 15.

Therefore, the solution to the problem is 225=15 \sqrt{225} = 15 .

Accordingly, the correct answer choice is option 2: 15.

Answer

15

Exercise #12

36= \sqrt{36}=

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Understand the definition of a square root.
  • Step 2: Identify which integer, when squared, gives 36.
  • Step 3: Verify this integer meets the required condition.
  • Step 4: Choose the correct answer from the given choices.

Now, let's work through each step:
Step 1: A square root of a number is a value that, when multiplied by itself, gives the original number. Here, we want y y such that y2=36 y^2 = 36 .
Step 2: We test integer values to find which one squared equals 36. Testing y=1,2,3,4,5, y = 1, 2, 3, 4, 5, and 6 6 gives:
- 12=1 1^2 = 1
- 22=4 2^2 = 4
- 32=9 3^2 = 9
- 42=16 4^2 = 16
- 52=25 5^2 = 25
- 62=36 6^2 = 36

Step 3: The integer 6 6 satisfies 62=36 6^2 = 36 . Therefore, 36=6 \sqrt{36} = 6 .

Step 4: The correct choice from the given answer choices is 6 (Choice 4).

Hence, the square root of 36 is 6 \mathbf{6} .

Answer

6

Exercise #13

441= \sqrt{441}=

Video Solution

Step-by-Step Solution

The root of 441 is 21.

21×21= 21\times21=

21×20+21= 21\times20+21=

420+21=441 420+21=441

Answer

21 21

Exercise #14

4= \sqrt{4}=

Video Solution

Step-by-Step Solution

To solve this problem, we'll determine the square root of the number 4.

  • Step 1: Recognize that the square root of a number is asking for a value that, when multiplied by itself, yields the original number. Here, we seek a number yy such that y2=4y^2 = 4.
  • Step 2: Identify that 44 is a perfect square. The numbers 22 and 2-2 both satisfy the equation 22=42^2 = 4 and (2)2=4(-2)^2 = 4.
  • Step 3: We usually consider the principal square root, which is the non-negative version. Thus, 4=2\sqrt{4} = 2.

Therefore, the solution to the problem is 2, which corresponds to the correct choice from the given options.

Answer

2

Exercise #15

64= \sqrt{64}=

Video Solution

Step-by-Step Solution

To solve this problem, we'll determine the square root of 64, following these steps:

  • Step 1: Identify the number whose square root we need to find. The number given is 64.
  • Step 2: Determine which number, when multiplied by itself, equals 64.
  • Step 3: Recall that 8×8=64 8 \times 8 = 64 .

Now, let's work through each step:

Step 1: We are tasked with finding 64 \sqrt{64} . The problem involves identifying the number which, when squared, results in 64.
Step 2: To find this number, we'll check our knowledge of squares. We know that 8 is a significant integer whose square results in 64.
Step 3: Compute: 8×8=64 8 \times 8 = 64 . Hence, 8 8 meets the requirement.

We find that the solution to the problem is 64=8 \sqrt{64} = 8 .

Answer

8

Topics learned in later sections

  1. Square Root of a Negative Number