Quantitative Aptitude
Let’s beat the cube root at its best….
Shikha Adya
shikha
August 17, 2015

So people! I hope you must have finished up with the last article on square root and in the same manner, we will proceed further to calculate cube root. The best part in calculating root problems here is you don’t need a calculator and it will hardly take much time to resolve the issue. Whether you are sitting in the examination hall or wish to show your brilliance before your friends, you just need a pen and paper to prove yourself. Let's Recall in square roots we made the table of squares similarly in cube root you have to follow the table of cubes as shown below :

cubeRoot1

Cube Root of Index four (For Perfect Cubes):

Problem 1:∛ 1728

Solutions:

  • Break the problem as we get the second half containing three digits (in cube root). 17 28
  • Check second half 728 the last digit lies in the table.
  • Last digit 8 come by cubing 2
cubeRoot2
  • The first half is 1 and is a perfect cube of itself.
  • Finally, Cube root of 1728 is 12

Problem 2:∛ 4096

Solutions:

  • Break the problem as we get the second half containing three digits (in cube root). 40 96
  • Check second half 096 the last digit lies in the table.
  • The last digit 6 come by cubing 2
cubeRoot3
  • The first half is 4 lies in between the cubes of 1 and 2 and always takes lower value.
cubeRoot4
  • Finally, the Cube root of 4096 is 16

Cube Root of Index five (For Perfect Cubes):

Problem 1:∛ 19683

Solutions:

  • Break the problem as we get the second half containing three digits (in cube root). 196 83
  • Check second half 683 the last digit lies in the table.
  • The last digit 3 come by cubing 7 and is the second half of the answer
cubeRoot5
  • The first half is 19 lies in between the cube of 2 and 3 and always takes lower value i.e. 2.
cubeRoot6
  • Finally, the Cube root of 19683 =27

Problem 2:∛ 46656

Solutions:

  • Break the problem as we get the second half containing three digits (in cube root). 466 56
  • Check second half 656 the last digit lies in the table.
  • The last digit 6 come by cubing 6 and is the second half of the answer
cubeRoot7
  • First half is 46 lies in the cube of 3 and 4 and always takes lower value i.e. 3
cubeRoot8
  • Finally, the Cube root of 46656 is 36

Cube Root of Index six (For Perfect Cubes):

Problem 1:∛ 804357

Solutions:

  • Break the problem as we get the second half containing three digits (in cube root). 804 357
  • Check the second half 357 the last digit lies in the table.
  • The last digit 7 comes by cubing 3 and is the second half of the answer
cubeRoot9
  • First half is 804 lies in a cube of 9 and 10 and always takes lower value i.e. 9
cubeRoot10
  • Finally, the Cube root of 804357 is 93

Solve ∛175616 and see how much you have learned ....

For right answer check the pdf file 

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Square Root

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