Find drag given reference area and speed

[korinnewade]

Homework Statement

What is the drag force on a 1.6 m wide, 1.4 m high car traveling at 30 m/s (approx 65 mph)?

Homework Equations

drag force=.5*p*v^2*coefficient of drag*A

The Attempt at a Solution

density of air depends on temp but that's not given so I used a density of 1.2 assuming there is a range of answers for this question. The drag coefficient for a car varies I used .25
I tried using the speed as m/s and mph in the equation. Reference area = 1.6*1.4

drag force=.5*1.2*484*.25*2.24

 

[PhanthomJay]

Where did the 484 come from?
Why would you use mph when your other units are SI?
The drag coefficient for cars vary all over the place depending on design.