Wednesday, 3 May 2017

How To Find Cube Root Of A Perfect Cube

how to find cube root

Since we now know how to find the cube of a number using the cube formula, let us discuss how to find the cube root of a perfect cube. Understanding how to find square root of a number will help us understand how to find a cube root easily. We can apply the same method to find the cube root of any perfect cube. But here’s the best part -- Finding cube root of a perfect cube is simpler than finding square root of a number.

Generally speaking, in the simplification section of the question paper of any competitive exam or an exam to pursue a career in IT, we are given to find cube roots of only perfect cubes. But if we are required to find the cube root of a number as part of a question from the approximation section, then it may or may not be a perfect cube.

How To Find Cube Root Of A Number In Two Easy Steps

Firstly, you must memorise the cubes of numbers from 1 to 15.
how to find cube root
We have already learnt that there is a certain pattern seen when it comes to cubes of numbers:
how to find cube root
SMART METHOD
How to find cube root of a perfect cube in a smart method is a 2-step process

Example 1: Find ∛551368
Solution:
Step1: Decide the unit’s place of the result.
551368 ends with 8 = Cube root will end with 2
_2

Step2: Leave the last 3 digits and find the immediate perfect cube before the remaining number.
The immediate perfect cube before 551 is 512 = 83
That is the number in our ten’s place
82

551368 = 82

Example 2: Find ∛50653
Solution:
Step1: Decide the unit’s place of the result.
50653 ends with 3 = Cube root will end with 7
_7

Step2: Leave the last 3 digits and find the immediate perfect cube before the remaining number.
The immediate perfect cube before 50 is 27 = 33
That is the number in our ten’s place
37

50653 = 37

If you have the cubes of numbers from 1 till 15 memorised, finding the cube root of any perfect cube should be a matter of seconds. The few extra minutes saved in the exam can go a long way in helping you secure your dream job!

Remember that knowing a technique is quite ineffective when it comes to applying them in the exam. To perfect these techniques and smart methods of finding cube root of a perfect cube, you must give it enough practice.

how to find cube root
See our expert faculty, Rohit Agarwal explain how to find cube root of a perfect cube in the video below.


Let us put your practice to test:

Question 1: Find ∛148877
Question 2: Find ∛46656

Please write your answers in the comments below and tell us how long it took you to find the right answers.

Hot Tip: If it takes you anything more than 3 seconds, you need more practice to perfect this smart method of how to find cube root of a perfect cube.
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