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685 LearnersLast updated on August 5, 2025

The cube root of 243 is 6.24025146916. The cube root of 243 is expressed as ∛243 in radical form, where the “ ∛ “ sign is called the “radical” sign. In exponential form, it is written as (243)1/3. If “m” is the cube root of 243, then, m3=243. Let us find the value of “m”.
The cube root of 243 is expressed as 3∛9 as its simplest radical form, since
243 = 3×3×3×3×3
∛243 = ∛(3×3×3×3×3)
Group together three same factors at a time and put the remaining factor under ∛ .
∛243= 3∛9
We can find cube root of 243 through a 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 243.
Step 1: Let a=243. Let us take x as 6, since, 63=216 is the nearest perfect cube which is less than 243.
Step 2: Apply the formula. ∛243≅ 6((63+2×243) / (2(6)3+243))= 6.24
Hence, 6.24 is the approximate cubic root of 243.


some common mistakes and solutions are given below:
Find (∛240/ ∛243) × (∛241/ ∛243) × (∛242/ ∛243)
(∛240/ ∛243) × (∛241/ ∛243) × (∛242/ ∛243)
= (∛240× ∛241× ∛242) / (∛243× ∛243× ∛243)
=(∛240× ∛241× ∛242)/ ((243)⅓)3
=(∛240× ∛241× ∛242)/243
=(6.214 × 6.223 × 6.231)/ 243
Answer: (6.214 × 6.223 × 6.231)/ 243
We used the fact that ((243)⅓)3=243 and then found the cube roots of 240,241, and 242 and simplified.
The length, breadth, and height of a cuboid is 5 unit, 4 unit, and 4.5 cm respectively. To find its volume, also find the measure of a side of a cube, whose volume is 243 cubic units.
Volume of a cuboid = length × breadth × height = 5 × 4 × 4.5 cubic units = 90 cubic units.
Given, Volume of a cube = 243 cubic units
⇒ side × side × side = 243 cubic units
⇒ side = ∛243
⇒ side = 6.24 units
Answer: Volume of the cuboid = 90 cubic units
Side length of the cube = 6.24 units
Applied the formula and concept of the volume of a cuboid and cube and solved.
Multiply ∛243 × ∛216
∛243×∛216
= 6.24×6
= 37.44
Answer: 37.44
We know that the cubic root of 216 is 6, hence multiplying ∛216 with ∛243.
What is ∛(243⁶^1/6) ?
∛(2436×1/6)
= (243)1/3
= 6.24…
Answer: 6.24
We solved and simplified the exponent part first using the fact that, (2436×1/6)=243, then solved.
Find ∛(243-(-100)).
∛(243-(-100))
= ∛(243+100)
=∛343
=7
Answer: 7
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.
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