Cube Root of 236 = 6.1797
Quick Answer
∛236 = 6.1797 (irrational)
Because 6.17973 ≈ 236
Cube Root Calculator
Use the calculator above to find the cube root of any real number (positive, negative, or decimal). See below the step-by-step method using Newton's iteration, plus a table of common perfect cubes.
Step-by-Step: Cube Root of 236
The cube root of 236 can be approximated using Newton's Method with the iterative formula:
xn+1 = (2 · xn + a / xn2) / 3
Starting from x0 = 78.6667 (rough estimate for 236):
| Iteration | x | x3 |
|---|---|---|
| 1 | 52.457156 | 144349.1503 |
| 2 | 35.000025 | 42875.0932 |
| 3 | 23.397568 | 12808.9092 |
| 4 | 15.742076 | 3901.0905 |
After 4 iterations the value converges to ∛236 ≈ 6.1797.
Why does this converge?
Newton's Method is a root-finding algorithm. For ∛a, we solve x3 − a = 0. The iteration uses the derivative (3x2) to refine each estimate. Convergence is quadratic — each iteration roughly doubles the digits of precision.
Formula
The cube root of a number a is the value x such that:
x3 = a ⇔ ∛a = x
Every real number has exactly one real cube root. Unlike the square root, the cube root is defined for negative inputs: ∛(−a) = −∛a.
How to Calculate Cube Roots
For perfect cubes (8, 27, 64, 125, …) the cube root is an integer — just recall the cube of small integers.
For other numbers, use Newton's Method:
- Start with a rough estimate (e.g. x0 = a / 3).
- Apply xn+1 = (2xn + a/xn2) / 3.
- Repeat 3–4 times — the value converges fast (each step roughly doubles the digits of precision).
Nearby Cube Roots
Perfect Cube Roots Table
Common perfect cubes from 1 to 1000. For the full table 1–100, see our cube root chart 1 to 1000.
| n | ∛n |
|---|---|
| 1 | 1 |
| 8 | 2 |
| 27 | 3 |
| 64 | 4 |
| 125 | 5 |
| 216 | 6 |
| 343 | 7 |
| 512 | 8 |
| 729 | 9 |
| 1000 | 10 |
Want the Simplified Radical Form?
The decimal value above is useful for measurements, but in algebra problems you often need the simplified radical form. Try our Simplify Cube Root Calculator to see ∛236 in simplest form (e.g. 2∛3 instead of 6.1797).
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Related Calculators
- Simplify Cube Root — radical form (e.g. ∛24 = 2∛3)
- Cube (n3) Calculator — the inverse operation
- Is 236 a Perfect Cube? — verdict + proof
- Square Root Calculator — decimal square root