Microsoft Excel: Raise A Number To A Fraction To Find The Square Or Third Root

Article by Mr Excel (11,387 pts ) , published Jul 1, 2008

Problem: Excel offers a SQRT function to find the square root of a number. What if you need to figure out the third root or the fourth root?

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Strategy: You can raise a number to a fraction to find a root. To find the square root of a number, you can raise the number to (1/2). To find the cube root of a number, you can raise the number to (1/3). To find the eighth root of a number, you can raise the number to (1/8).

Here are several examples.

If you need to find the square root, you can use the SQRT function, as shown in Fig. 436.

As shown in Fig. 437, you can also raise the number to the one-half (1/2) power. Or, you can raise the number to 0.5, as shown in Fig. 438.

To find the cube root of a number, you can raise the number to the one third (1/3) power, as shown in Fig. 439.

To find the fourth root of a number, raise the number to either one-forth (1/4) or 0.25 power, as shown in Fig. 440 and Fig. 441, respectively. To find the seventeenth root of a number, raise it to the one-seventeenth (1/17) power, as shown in Fig. 442.

Summary: Although Excel only offers a function for a square root, you can use the technique of raising to a fractional power in order to determine any root of a number.

Commands Discussed: Exponent operator

Functions Discussed: =SQRT()


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Images

Fig. 436Fig. 437Fig. 438Fig. 439Fig. 440Fig. 441Fig. 442
 
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