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Last updated on November 30th, 2024

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Cube Root of 128

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Foundation
Intermediate
Advance Topics

The cube root of 128 is the value that, when multiplied by itself three times (cubed), gives the original number 128. Do you know? Cube roots apply to our real life also, like that for measuring dimensions, density and mass, field of engineering etc.

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What Is the Cube Root of 128?

The cube root of 128 is 5.03968419958. The cube root of 128 is expressed as βˆ›128 in radical form, where the β€œβˆ›"  sign is called the β€œradical” sign. In exponential form, it is written as (128)β…“. If β€œm” is the cube root of 128, then, m3=128. Let us find the value of β€œm”.
 

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Finding the Cube Root of 128

The cube root of 128 is expressed as 4βˆ›2 as its simplest radical form,

 

since 128 = 2Γ—2Γ—2Γ—2Γ—2Γ—2Γ—2


βˆ›128 = βˆ›(2Γ—2Γ—2Γ—2Γ—2Γ—2Γ—2)


Group together three same factors at a time and put the remaining factor under the βˆ› .


βˆ›128= 4βˆ›2 


 We can find cube root of 128 through a method, named as, Halley’s Method. Let us see how it finds the result.
 

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Cube Root of 128 By Halley’s Method

Now, what is Halley’s Method? It is an iterative method for finding cube roots of a given number N, such that, x3=N, where this method approximates the value of β€œx”.


Formula is βˆ›aβ‰… x((x3+2a) / (2x3+a)), where 


a=given number whose cube root you are going to find.


x=integer guess for the cubic root


 Let us apply Halley’s method on the given number 128.


Step 1: Let a=128. Let us take x as 5, since, 53=125 is the nearest perfect cube which is less than 128.


Step 2: Apply the formula.  βˆ›128β‰… 5((53+2Γ—128) / (2(5)3+128))= 5.039…


Hence, 5.039… is the approximate cubic root of 128.
 

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Important Glossaries for Cubic Root of 128

  • Integers:  Integers can be a positive natural number, negative of a positive number, or zero. We can perform all the arithmetic operations on integers. The examples of integers are, 1, 2, 5,8, -8, -12, etc.

 

  • Whole numbers: The whole numbers are part of the number system, which includes all the positive integers from 0 to infinity. 

 

  • Square root: The square root of a number is a value β€œy” such that when β€œy” is multiplied by itself β†’ y ‫ y, the result is the original number.

 

  • Polynomial: It is an algebraic expression made up of variables like β€œx” and constants, combined using addition, subtraction, multiplication, or division, where the variables are raised to whole number exponents.

 

  • Approximation:  Finding out a value which is nearly correct, but not perfectly correct.

 

  • Iterative method: This method is a mathematical process which uses an initial value to generate further and step-by-step sequence of solutions for a problem.
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