Cube roots

[murali0298]

This one was confusing...
The cube root of 274625 is _________________.
Is there any general method of finding cube roots instead of thinking of cubes near the number given and do the approximation???

[sxk1693]

This is kind of easy. i like these problems. You know it must end with a five. 60^3 = 216000. 70^3 = 343000. Your answer is 65.

[BlasianAsian]

Yeah. It's just a matter of guessing and checking. I think someone asked this type of question already.

[michel470]

Take the number in groups of 3's
274|625
Find a cube whose units digit is the same as the unit's digit of the whole number. 5^3=125 So the units digit of your answer will be 5.
Take the next three numbers and find the closest cube under it. In this case, the closest cube under 274 is 6(6^3=216). That number is your tens digit.
A=65

50653
Take by 3's
50|653
You know 7^3=343, and this number ends with a 3, so 7 will be the units digit of your answer.
Take the next three, or in this case, two. The closest cube under 50 is 3(3^3=27)
A=37

[sxk1693]

What about cube roots of that end up as 3 digit numbers!!!! I encountered this today

[BlasianAsian]

Can you rephrase that?

[sxk1693]

Im sorry grammatical mistake. One of the questions i had was the cube root of 2924207. The answer was 143. How would do this. would you have to realize 140^3 = 2744000?

[nsguy1350]

You should know that 14^3 = 2744, so 140^3 = 2744000. Ends in a 7, so yes, 3 works.
143 is your answer.

[murali0298]

[BlasianAsian]

Deleted....

[nsguy1350]

[BlasianAsian]

Fail. My eyes decieve me. Sorry, I'll delete it.