Tell What Restrictions, If Any, Must Be Made On $s, k$

Short Answer

Tell what restrictions, if any, must be made on $s, k$ , and $w$ to guarantee that $d$ is a real number. Assume that $\mathrm{s}, \mathrm{k}$ , and $\mathrm{w}$ are all real numbers and that the denominator is not zero.
$\mathrm{d}=\frac{\sqrt{\mathrm{skw}}}{\mathrm{kw}}$