The trailers are 9 foot plus tall, but you can't use that in your calculation. The 9 foot is from the ground, and the trailers don't drag the ground. You would need to know the height of the front wall, usually around 7.5 to maybe 8 feet. Some more, some less.
To be accurate, you need to know the height of the front wall, and the width, which is given. Also, the frontal area in tow vehicle ratings, is for a flat nose trailer, which I have, but not that many are. If you want to get in to slopes and curves, and "V" nose.... that would require a calculus class in night school.
Well, hope some of this helped. Just remember, height is from the ground, not true height of front wall.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT