

Cube Root - Overview
Whenever you come across the word cube root the two words that come into our mind are cube and roots of a tree. Actually the concept is a bit similar in this sense, root actually refers to the primary source of origin. So we should think about what number you should refer to. That cube will give you a particular number that you are looking for.
Cube root of a number x is a number y only when y×y×y= x. All the nonzero real numbers have one real cube root and along with it a pair of complex conjugate cube roots, and all non zero complex numbers have three different complex roots that are cube roots.
The cube root of any number in brief can be defined as the factor that we multiply by itself three times to get the particular numbers. Remember that the cube root of a number is exactly opposite of the cubing of a number.
The process of cubing is similar to squaring, only that the number is multiplied three times instead of two times as in squaring. The exponent used for cubes is 3, which is also denoted by the superscript³. Examples are 4³ = 4*4*4 = 64 or 8³ = 8*8*8 = 512 etc.
To find the volume of the cube, we have volume = side3, but if we want to find the side of a cube we have to take the cube root of the volume. Thus, we can say that the cube root is the inverse operation of cubing a number. The cube root symbol is 3√.
Let’s suppose we need to find the value of cube root of 2 is a value that is obtained by multiplying that number three times. It is expressed in the form of ‘3√2’. The meaning of cube root is basically the root of a number that is generated by taking the cube of another number. Hence, if the value of 3√2=x, then x3 =2 and we need to find the value of x.
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We can define the cube root of a number as a special value that, when used in a multiplication exactly three times, gives us that number.For example, 3 × 3 × 3 equals 27, so the cube root of 27 is 3.
The Cube Root Symbol
The special symbol given below signifies the "cube root", it is known to be the "radical" symbol (the symbol can be used for square roots) and with a little three to mean cube root.
3√
You can use it like this, the cube root of 27 is : 3√27=3 (we say "the cube root of 27 equals to 3")
Find the Cube of Fraction
You can find the cube of a fraction the same way as you are finding the cube of a number. You just need to multiply the fraction three times. Just take the example of ⅔. You can get the cube of this fractional number by first multiplying the number in the numerator 3 times that is here you can first multiply the number 2 three times, 2×2×2 and as a result you will get 8 that is the Cube of the number 2 which is in your numerator.
Now move towards the denominator, here in your denominator there is 3, you can get its cube by multiplying it 3 times, that is 3×3×3 hereafter cubing the number 3 you are going to get 27 as a result, which is the Cube of your number 3, registered here as the denominator. So as a result you are going to get 8/27. This 8/27 is the Cube of your number ⅔ which you can get either by doing the multiplication of these numbers separately or you can do the multiplicity of the whole fraction three times, that is ⅔ × ⅔ × ⅔. Giving you the result of 8/27.
You Can Also Cube Negative Numbers
Have a look at this:When we cube +5 we generally get +125: +5 × +5 × +5 = +125
When we cube −5 we get the number −125: −5 × −5 × −5 = −125. So the cube root of the number −125 is equal to −5
Cube Roots (For Integer Results 1 through 10)
Cube root of 1 is 1
Cube root of 8 is 2
Cube root of 27 is 3
Cube root of 64 is 4
Cube root of 125 is 5
Cube root of 216 is 6
Cube root of 343 is 7
Cube root of 512 is 8
Cube root of 729 is 9
Cube root of 1000 is 10
What is the Meaning of Cube Root?
The cube root of a number a is that number which when multiplied by itself three times gives the number ‘a’ itself.
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Let’s see for example,
23 =8, or the cube root of the number 8 is 2
33 = 27, or the cube root of the number 27 is 3
43 = 64, or the cube root of 64 is 4
53 = 125, or the cube root of 125 is 5
The symbol of the cube root is a3 or 3√a
Thus, the cube root of 125 is represented as 3√125=5 and that of 27 can be represented as 3√27 equals 3 and so on.
We know that the cube of any number is found by multiplying that number three times. And the cube root of a number can be defined as the inverse operation of cubing a number.
For Example:
If the cube of a number 63 = 216
Then the cube root of ∛216 is equal to 6.
Cube root of any largest number can be easily found in four ways:
Prime factorization Method
Long Division Method
Using Logarithms
Bisection Method
A Few Properties of Cube Root
The cube root of all the odd numbers is an odd number. For example ∛125 = 5, ∛27 = 3.
Cube root of all even natural numbers is even. For example: ∛8 = 2,∛64 = 4.
The cube root of a negative integer always results in negative.
Let’s Know Cube Roots of Some Numbers
The cube root of 16 is 2.1598
The cube root of 5 is 1.7099
The cube root of 6 is 1.1871
The cube root of 10 is 2.1544
The cube root of 12 is 2.2894
The cube root of 7 is 1.912
The cube root of 0 is 0
The cube root of 20 is 2.7144
What are Perfect Cubes?
A perfect cube of an integer is that integer which is actually equal to some other integer raised to the third power. We refer to raising the number to the third power as cubing the number.
The example that we just saw also happens to be an example of a perfect cube. A perfect cube can be defined as a cube of a whole number. 27 is a perfect cube because to get the number 27, we need to cube the number 3. Think back to the cube. It's a perfect cube because all the building blocks are whole pieces. To find a perfect cube, we take any whole number and cube it, meaning we multiply it by itself three times. Knowing the perfect cubes will help us to find cube roots easily. If we started with the 1 and found perfect cubes for our numbers up to 10, we would get this list:1 2 3 4 5 6 7 8 9 10.
Perfect Cube :1 8 27 64 125 216 343 512 729 1000 .
What is a Cube Root Calculator?
Cube root calculator is a tool that will help you to find the cube root of a particular number. This calculator is free. By using the cube root calculator you can find the cube root of a number free without giving any charge.
How can you use a Cube Root Calculator?
To use the cube root calculator follow the steps given below. It will make your work of calculating cube easy.
Step 1 : You should write any integer or decimal number that you need to find the cube root of in the enter number box.
Step 2: Click on 'calculate' and you will get the step wise result of the cube root of the number you are looking for.
Step 3: Click on the reset button and you can re enter the new number and find the cube root of another number.
Questions to be Solved
Question: What is the Cube Root of 30?
Answer: Well, 3 × 3 × 3 = 27 and 4 × 4 × 4 = 64, so we can guess the answer is between 3 and 4.
Let's try the following 3.5: 3.5 × 3.5 × 3.5 = 42.875
Let's try the following 3.2: 3.2 × 3.2 × 3.2 = 32.768
Let's try the following 3.1: 3.1 × 3.1 × 3.1 = 29.791
Now we are getting closer, but slowly at this point, we can use a calculator and it says:
3.1072325059538588668776624275224...... but the digits just go on and on, without any kind of pattern. So even the calculator's answer can be known only as an approximation !
Question 2:What is the Cube Root of 1728?
Answer: To find the cube root of number such as that of 1728 follow the below step and you can easily get the cube root.The factors of 1728 are given as,1728 = 12 × 12 × 12∛1728 = ∛(12 × 12 × 12)∛1728 = 12
FAQs on Cube Root
1. What exactly is a cube root?
A cube root of a number is a special value that, when multiplied by itself three times, gives the original number. For example, the cube root of 27 is 3 because 3 × 3 × 3 = 27. It is the inverse operation of finding the cube of a number.
2. What is the symbol used to represent a cube root?
The symbol for the cube root is the radical sign (√) with a small 3 written as an index, like this: ∛. So, the cube root of a number 'x' is written as ∛x. It can also be expressed using exponents as x1/3.
3. What is the prime factorization method for finding the cube root of a perfect cube?
The prime factorization method is a standard way to find the cube root of a perfect cube as per the NCERT syllabus. The steps are:
- Resolve the number into its prime factors.
- Group the identical factors into triplets (groups of three).
- From each triplet, take one factor.
- Multiply these factors together to get the cube root.
4. How do you find the cube root of 64?
To find the cube root of 64, you need to find a number that, when multiplied by itself three times, equals 64. By testing small integers, we find that 4 × 4 × 4 = 64. Therefore, the cube root of 64 is 4.
5. Can the cube root of a negative number be found? If so, what is the cube root of -27?
Yes, you can find the cube root of a negative number. The cube root of a negative number will always be negative. For ∛-27, we look for a number that, when cubed, gives -27. Since (-3) × (-3) × (-3) = -27, the cube root of -27 is -3.
6. What is the difference between finding a square root and a cube root?
The main differences between square roots and cube roots are:
- Factor Grouping: For a square root, you group prime factors in pairs (groups of 2). For a cube root, you group them in triplets (groups of 3).
- Handling Negatives: The real square root of a negative number is undefined, while the cube root of a negative number is always a real, negative number.
- Symbol: The square root symbol is √ (or √ with an implied index of 2), whereas the cube root symbol explicitly uses an index of 3 (∛).
7. How can you estimate the cube root of a number that is not a perfect cube, like 100?
To estimate the cube root of a non-perfect cube, you can find the two closest perfect cubes. We know that 4³ = 64 and 5³ = 125. Since 100 lies between 64 and 125, its cube root must lie between 4 and 5. As 100 is closer to 125 than to 64, we can estimate that its cube root will be closer to 5, likely around 4.6.
8. Why is it useful to memorise the cubes of numbers from 1 to 10 when calculating cube roots?
Memorising the cubes of the first 10 numbers is extremely useful for two main reasons:
- Unit Digit Clues: The unit digit of a perfect cube is determined by the unit digit of its root. Knowing these helps you quickly identify the last digit of the cube root.
- Estimation: It allows you to quickly 'bracket' a large number between two perfect cubes, making the process of estimation for non-perfect cubes much faster and more accurate.
9. Where are cube roots used in real-world applications?
Cube roots have practical applications, especially in fields related to three-dimensional space. A primary example is in geometry, where if you know the volume (V) of a cube, you can find the length of its side (s) by calculating the cube root of the volume (s = ∛V). This is crucial in design, engineering, and physics for problems involving volume and dimensions.
10. Why does the cube root of an even number have to be even?
This is because of the properties of multiplication. An even number is defined as being divisible by 2. When you cube an even number (even × even × even), the result is always even because the factor of 2 is preserved. Therefore, when you reverse the process by taking the cube root of a perfect cube that is even, its root must also be even to have produced that result.

















