Question 824619
Do you mean ,  solve for R ?


Multiplicative Inverse of {{{pi}}};
Exponentiate members to the half-power;
Additive Inverse of R;-------------(this was a mistake.  See below for better response)
Multiplicative Inverse of {{{-1}}}.


Those are the justification for the sequence of steps to solve.  Can you use those in order to give the steps?



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Here, is better.  You want R as the "subject" for the given equation of A.  Again, I will give only the laws which you can use, but not the actual mathematical/algebraic steps.


Multiplicative Inverse of {{{pi}}};
Exponentiate to the half power, both sides;
Additive Inverse of {{{r/2}}};
You should supply the steps yourself, but should then have the formula for R as a result.