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108 LearnersLast updated on April 2nd, 2025
Cube Root of 639
A number we multiply by itself three times to get the original number is its cube root. It has various uses in real life, such as finding the volume of cube-shaped objects and designing structures. We will now find the cube root of 639 and explain the methods used.
What is the Cube Root of 639?
We have learned the definition of the cube root. Now, let’s learn how it is represented using a symbol and exponent. The symbol we use to express the cube root is the radical sign (∛), and the exponent we use is ⅓. In exponential form, ∛639 is written as 639(1/3). The cube root is just the opposite operation of finding the cube of a number. For example: Assume ‘y’ as the cube root of 639, then y3 can be 639. Since the cube root of 639 is not an exact value, we can write it as approximately 8.6206.
Finding the Cube Root of 639
Finding the cube root of a number is to identify the number that must be multiplied three times resulting in the target number. Now, we will go through the different ways to find the cube root of 639. The common methods we follow to find the cube root are given below:
- Prime factorization method
- Approximation method
- Subtraction method
- Halley’s method
To find the cube root of a non-perfect number, we often follow Halley’s method. Since 639 is not a perfect cube, we use Halley’s method.
Cube Root of 639 by Halley’s method
Let's find the cube root of 639 using Halley’s method.
The formula is ∛a ≅ x((x3 + 2a) / (2x3 + a))
where: a = the number for which the cube root is being calculated
x = the nearest perfect cube
Substituting, a = 639; x = 8
∛a ≅ 8((83 + 2 × 639) / (2 × 83 + 639))
∛639 ≅ 8((512 + 2 × 639) / (2 × 512 + 639))
∛639 ≅ 8.6206 The cube root of 639 is approximately 8.6206.
Common Mistakes and How to Avoid Them in the Cube Root of 639
Finding the perfect cube of a number without any errors can be a difficult task for the students. This happens for many reasons. Here are a few mistakes the students commonly make and the ways to avoid them:
Mistake 1
Trying to find perfect cube roots for non-perfect cube numbers.
Children always try to calculate an exact whole number for the cube root of numbers like 639, which are not perfect cubes. For example: They assume that they would get an exact whole number for 639. To avoid this error, memorize that some numbers don't have a perfect cube root, that is, the cube root of 639 is approximately 8.6206.
Cube Root of 639 Examples:
Problem 1
Imagine you have a cube-shaped box that has a total volume of 639 cubic centimeters. Find the length of one side of the box equal to its cube root.
Side of the cube = ∛639 = 8.62 units
Explanation
To find the side of the cube, we need to find the cube root of the given volume.
Therefore, the side length of the cube is approximately 8.62 units.
Problem 2
A company manufactures 639 cubic meters of material. Calculate the amount of material left after using 200 cubic meters.
The amount of material left is 439 cubic meters.
Explanation
To find the remaining material, we need to subtract the used material from the total amount:
639 - 200 = 439 cubic meters.
Problem 3
A container holds 639 cubic meters of liquid. Another container holds a volume of 150 cubic meters. What would be the total volume if the containers are combined?
The total volume of the combined containers is 789 cubic meters.
Explanation
Let’s add the volume of both containers:
639 + 150 = 789 cubic meters.
Problem 4
When the cube root of 639 is multiplied by 3, calculate the resultant value. How will this affect the cube of the new value?
3 × 8.62 = 25.86
The cube of 25.86 = 17,298.19
Explanation
When we multiply the cube root of 639 by 3, it results in a significant increase in the volume because the cube increases exponentially.
Problem 5
Find ∛(500 + 139).
∛(500 + 139) = ∛639 ≈ 8.62
Explanation
As shown in the question ∛(500 + 139), we can simplify that by adding them.
So, 500 + 139 = 639.
Then we use this step: ∛639 ≈ 8.62 to get the answer.
FAQs on 639 Cube Root
1.Can we find the Cube Root of 639?
2.Why is Cube Root of 639 irrational?
3.Is it possible to get the cube root of 639 as an exact number?
4.Can we find the cube root of any number using prime factorization?
5.Is there any formula to find the cube root of a number?
Important Glossaries for Cube Root of 639
- Cube root: The number that is multiplied three times by itself to get the given number is the cube root of that number.
- Perfect cube: A number is a perfect cube when it is the product of multiplying a number three times by itself. A perfect cube always results in a whole number. For example, 3 × 3 × 3 = 27, therefore, 27 is a perfect cube.
- Exponent: The exponent form of the number denotes the number of times a number can be multiplied by itself. In 639(1/3), ⅓ is the exponent which denotes the cube root.
- Radical sign: The symbol that is used to represent a root which is expressed as (∛).
- Irrational number: The numbers that cannot be put in fractional forms are irrational. For example, the cube root of 639 is irrational because its decimal form goes on continuously without repeating the numbers. ```
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Jaskaran Singh Saluja
About the Author
Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.
Fun Fact
: He loves to play the quiz with kids through algebra to make kids love it.
