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# How to find the largest 4 digit no. which is a perfect cube? pls help me fast  and im getting prime factors as 3 x 3 x 11 x 101 . So can u pls help me with the next step. my exams r nearing.pls help me as fat as u can

Asked by Amey Pathak(OUR OWN ENGLISH HIGH SCHOOL) , on 6/9/11

Hi!

The largest 4-digit perfect cube can be obtained by cubing some natural numbers at random.
Let’s take the number say 10.
103 = 1000 which is very less than largest 4-digit number
Let’s now take 15.
153 = 3375 which is still less than largest 4-digit number
Now let us take 20.
203 = 8000
Now, let’s  take 21.
213 = 9261
Now take 22.
223 = 10648 which is greater than largest 4-digit number (9999)
So, we can conclude that 9621 is the largest 4-digit perfect cube.

Cheers!

Posted by Lalit Mehraon 7/9/11

This conversation is already closed by Expert

i know adout 5 digit no.

The potentially largest number is 99,999. Take the cube root of 99,999 and you get 46.4... Take 46^3 and you get = 97336,

Posted by Davis Dayal(GURU NANAK PUBLIC SCHOOL) on 6/9/11

cube root of 9999 is 21.543628731482663. Take 21and the further

Posted by Davis Dayal(GURU NANAK PUBLIC SCHOOL) on 6/9/11

sir my method is right

Posted by Davis Dayal(GURU NANAK PUBLIC SCHOOL) on 22/9/11