Answer:
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<em>The last option matches the correct solution</em>
Step-by-step explanation:
<u>Equation Solving</u>
We have the following equation:

And it's required to solve it for r.
Solving this equation needs to perform some operations to have the r isolated from any other variables or constants.
It can be done by conveniently operating on both sides as follows:
Eliminate the denominator by multiplying by 3:

Move
to the other side by dividing by
:

Swapping sides to have r at the left side:

Finally, take the cubic root and leave r alone:
![\displaystyle r=\sqrt[3]{\frac{3V}{4\pi}}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%20r%3D%5Csqrt%5B3%5D%7B%5Cfrac%7B3V%7D%7B4%5Cpi%7D%7D)
The last option matches the correct solution