An empirical formula by E. F. Dubois relates the surface area $S$ of a human body (in square meters) to its weight $W$ (in kilograms) and its height $H$ (in centimeters). The formula, given by $$S=0.007184 W^{0.425} H^{0.725}$$
is used by physiologists in metabolism studies.
a. Find the domain of the function $S$.
b. What is the surface area of a human body that weighs $70 \mathrm{kg}$ and has a height of
$178 \mathrm{cm} ?$