Current Attempt in Progress

$($See Fluids in the News article titled "Modeling parachutes in a water tunnel".$)$ Flow characteristics for a $33-$ft$-$diameter prototype parachute are to be determined by tests of a $1\mathrm{.}0-$ft$-$diameter model parachute in a water tunnel. Some data collected with the model parachute indicate a drag $F_m=20lb$ when the water velocity is $4f\frac{t}{s}.$

$($a$)$ Find the predictor equation. Assume the drag to be a function of the velocity, $V,$ the fluid density, $,$ and the parachute diameter, $D.$ Note that model variables have subscripts $m.$