Question

Shortcut to find cube root of non perfect cube root

Answer 1

This method is not as straight as finding cube root of perfect cubes so I will explain with an example, let’s take 260 as an example.

As we know 260 is a non perfect cube,

Step 1- Find the integral part

First we have to find out the integral cubes root between which 260 is. At this point you must be aware that 260 lies between 216 (cube of 6) and 343 (cube of 7). So integral part of cube root will be 6.

Step 2- Finding the decimal part of cube root

Divide 260 by square of 6 i.e. 36

260/36=7.2

Now subtract 6 from 7.2 and the result is divided by 3

7.2 – 6 = 1.2 and NOW divided by 3=>1.2/3= 0.4

step 3- Add this decimal number to to the integral cube root i.e. 0.4+ 6 = 6.4 Thus the cube root of 260 is 6.4

Now the actual cube root will not be 6.4 but this is an approximation method and results will be always correct to only first decimal place.

Hope it helps.