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810 LearnersLast updated on August 5, 2025

The cube root of 7 is 1.91293118277. The cube root of 7 is expressed as ∛7 in radical form, where the “∛" sign is called the “radical” sign. In exponential form, it is written as (7)⅓. If “m” is the cube root of 7, then, m3=7. Let us find the value of “m”.
The Prime Factorization of 7 is 7, so, the cube root of 7 is expressed as ∛7 as its simplest radical form. We can find cube root of 7 through another method, named as, Halley’s Method. Let us see how it finds the result.
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 “x”.
Formula is ∛a≅ 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 7.
Step 1: Let a=7. Let us take x as 1, since, 1 is the nearest perfect cube which is less than 7.
Step 2: Apply the formula. ∛7≅ 1((13+2×7) / (2(1)3+7))=15/9 ≅ 1.667
Hence, 1.667 is the approximate cubic root of 7.


some common mistakes and their solutions are given below:
Find ∛7 / ∛8
∛7/ ∛8= 1.913 / 2 =0.9565
Answer: 0.9565
We know that the cubic root of 8 is 2, hence dividing ∛7 by 2.
The Volume of a cube is 7 cubic centimeters, find the length of one side of the cube.
We know that, (side of a cube)3=Volume of a cube
⇒side of the cube = ∛(Volume of the cube)
⇒side of the cube = ∛7
⇒ side of the cube = 1.913 cm
Answer: 1.913 cm
We applied the formula for finding the volume of a cube, and inverted it to find the measure of one side of the cube.
Subtract ∛7 - ∛8
∛7-∛8= 1.913–2= -0.087
Answer: -0.913
We know that the cubic root of 8 is 2, hence subtracting ∛8 from ∛7.
What is ∛(7² ) ?
∛(72) = ∛49 = 3.659…
Answer: 3.659…
We first found the square value of 7, which is 49, and then found out the cube root of 49.
Find ∛(7+1).
∛(7+1) = ∛8=2
Answer: 2
Simplified the expression, and found out the cubic root of the result.

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.
: He loves to play the quiz with kids through algebra to make kids love it.






