The cube root of 3 is , and unlike many radicals, it does not simplify at all.
Quick Answer:
Result:
Notation: or
Method shown: estimation between neighbouring cubes
Approximate value: (to 3 decimal places, irrational)
Exact form: (already in simplest radical form)
Quick Reference Table
Number | Simplified cube root | Decimal (3 dp) |
|---|---|---|
Where the Cube Root of 3 Appears
The cube root of 3 is the edge length of a cube whose volume is 3 cubic units. It also turns up in engineering scaling laws: to triple the volume of a cube-shaped object while keeping its proportions, every edge must grow by a factor of , not by 3.
What Is the Cube Root of 3?
The cube root of a number is the value that, multiplied by itself three times, gives that number. Since no whole number cubed equals 3, the cube root of 3 sits between and .
The result is an irrational number that never terminates and never repeats. Because 3 is prime, it has no perfect-cube factor to pull out, so is already in its simplest form, a point that connects directly to the ideas in cube numbers and radicals.
How to Find the Cube Root of 3 (Methods)
Method 1: Estimation between neighbouring cubes
Locate 3 between the two nearest perfect cubes.
So lies between 1 and 2, and much closer to 1 because 3 is close to 1. Testing :
That is below 3, so try :
That is just above 3, so the answer sits between 1.44 and 1.45. Testing :
Final answer: to three decimal places.
Method 2: Why it will not simplify
Write 3 in terms of its prime factors.
For a factor to leave a cube root, it must appear three times. The single 3 has no group of three.
Final answer: is already in simplest radical form.
Common Mistakes With Cube Root of 3
Mistake 1: Dropping the cube-root index
Where it slips in: writing the radical quickly.
Don't do this: writing when you mean the cube root.
The correct way: always show the index: . Without the little 3 it reads as a square root, giving instead of .
Mistake 2: Trying to simplify a prime radical
Where it slips in: assuming every cube root breaks down like .
Don't do this: writing as some product of smaller radicals.
The correct way: a prime number under a cube root has no perfect-cube factor, so it stays as .
Mistake 3: Confusing with or
Where it slips in: reading the radical as ordinary division.
Don't do this: answering 1.
The correct way: the cube root asks "what number cubed gives 3?" The answer is , not 1.
To build cube-root fluency with a teacher, explore Bhanzu's algebra tutor or math classes online.
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