How would you do cube root of 0.0000027 without a calculator

[yh4747]

Please explain step by step

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[syeh3]

You have to convert to scientific notation and them do it there. Much easier!

 

[syeh3]

27 x10^-7 which is around 3^3 if you ignore the scientific notation

 

[amy_k]

If you convert to scientific notation we would need a power that is divisible by 3, since cube root raises the value to the power of 1/3, we will be dividing the exponent by 3.

So we would have to approximate (2.7x10^-6)^1/3, which could go something like this:

1 cubed is 1
1.5 cubed is 3.375

So cube root of 2.7 is between 1 and 1.5, you would have to have answer choices that are reasonable to choose from without a calculator. Actual answer is 1.39.

Cube root of the "x10^-6" is x10^-2

So the answer is approximately 1.39x10^-2 or 0.0139

 

[2THDDS]

(2.7 x 10^-6)^1/3

equals
2.7^(1/3) x (10^-6)^(1/3)

equals
1.4 x 10^-2

 

[DAT Destroyer]

Change it to 2.7*10^-6.
We know that square root of 2 is 1.4 and square toot of 3 is 1.7. Square root of 3.7 should be between those 2 values and closer to 1.7
So the answer is 1.6*10^-3

Keep studying the math it is a very challenging section.

Take care..nancy

 

[2THDDS]

Change it to 2.7*10^-6.
We know that square root of 2 is 1.4 and square toot of 3 is 1.7. Square root of 3.7 should be between those 2 values and closer to 1.7
So the answer is 1.6*10^-3

Keep studying the math it is a very challenging section.

Take care..nancy

it's cube root 🙂

 

[DAT Destroyer]

it's cube root 🙂

🙂

 

[alexis2010]

just curious where did you find this question?

 

[DAT Destroyer]

it's cube root 🙂

Ohh sorry i read it as square root.
to take the cube root change it to 2.7x10^(-6)
cube root of 10^(-6) is 10^(-2)
to find a cube root of 2.7 we know it should be between 1 and 2 and should be little less than 1.5 because 1.5^3 = 3.375
the answer should be between 1.3 and 1.4

you can always look at the answers and eliminate the obvious wrong answers.