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How to Put Cube Root Into A Calculator

Reviewed by Calculator Editorial Team

Calculating cube roots is a fundamental math operation that finds applications in geometry, algebra, and real-world measurements. Whether you're solving equations, designing structures, or analyzing data, understanding how to calculate cube roots accurately is essential. This guide explains how to put cube root into a calculator and provides alternative methods for when a calculator isn't available.

How to Calculate Cube Root

The cube root of a number \( x \) is a value that, when multiplied by itself three times, gives the original number. Mathematically, it's represented as \( \sqrt[3]{x} \). Calculating cube roots can be done using a calculator or through manual methods.

Cube Root Formula

For a number \( x \), the cube root is calculated as:

\( \sqrt[3]{x} = x^{1/3} \)

To find the cube root of a number, you can use the following steps:

  1. Identify the number for which you want to find the cube root.
  2. Use a calculator to input the number and apply the cube root function.
  3. If using a scientific calculator, look for the \( x^y \) function and input \( x^{1/3} \).
  4. For graphing calculators, use the cube root function directly if available.

Calculator Methods

Most modern calculators have built-in functions for calculating cube roots. Here's how to use them:

Scientific Calculator

  1. Turn on your scientific calculator.
  2. Enter the number you want to find the cube root of.
  3. Press the \( x^y \) button (often labeled as \( y^x \) or \( \wedge \)).
  4. Enter 1/3 as the exponent.
  5. Press the equals (=) button to get the result.

Graphing Calculator

  1. Open your graphing calculator.
  2. If the cube root function is available, select it from the function menu.
  3. Enter the number inside the parentheses.
  4. Press the enter or equals button to see the result.

Online Calculator

  1. Open an online calculator tool.
  2. Look for a cube root function or exponent function.
  3. Input the number and apply the cube root function.
  4. Click calculate to see the result.

Manual Methods

If you don't have access to a calculator, you can estimate cube roots using manual methods:

Estimation Using Known Cubes

  1. Identify perfect cubes near your target number.
  2. For example, to find \( \sqrt[3]{28} \), note that \( 3^3 = 27 \) and \( 4^3 = 64 \).
  3. Since 28 is closer to 27, the cube root is between 3 and 4.
  4. Refine your estimate by testing numbers like 3.05 and 3.1.

Long Division Method

  1. Write the number in groups of three digits from the decimal point.
  2. Find the largest number whose cube is less than or equal to the first group.
  3. Subtract and bring down the next group.
  4. Repeat the process to find the cube root digit by digit.

Examples

Let's look at some examples of calculating cube roots:

Example 1: \( \sqrt[3]{27} \)

Since \( 3 \times 3 \times 3 = 27 \), the cube root of 27 is 3.

Example 2: \( \sqrt[3]{64} \)

Since \( 4 \times 4 \times 4 = 64 \), the cube root of 64 is 4.

Example 3: \( \sqrt[3]{125} \)

Since \( 5 \times 5 \times 5 = 125 \), the cube root of 125 is 5.

Example 4: \( \sqrt[3]{216} \)

Since \( 6 \times 6 \times 6 = 216 \), the cube root of 216 is 6.

FAQ

What is the difference between square root and cube root?
The square root of a number \( x \) is a value that, when multiplied by itself, gives \( x \). The cube root is a value that, when multiplied by itself three times, gives \( x \).
How do I calculate the cube root of a negative number?
The cube root of a negative number is also negative. For example, \( \sqrt[3]{-8} = -2 \) because \( -2 \times -2 \times -2 = -8 \).
Can I use a calculator to find cube roots of decimals?
Yes, most calculators can handle decimal inputs. Simply enter the decimal number and apply the cube root function as you would with whole numbers.
What if my calculator doesn't have a cube root function?
If your calculator lacks a cube root function, you can use the exponent function with 1/3 as the exponent or estimate the cube root using manual methods.
Where are cube roots used in real life?
Cube roots are used in geometry to find the side length of a cube given its volume, in algebra to solve cubic equations, and in physics for calculations involving volume and density.