Oh, and if you guys have time, could you perhaps rate it on the NXTLOG? Thanks!
MsRowdyRedhead,
Thanks! And thanks for the comment on the NXTLOG too.

Lol, that would be funny!
Blade,
Great! I hope you enjoy it, and thanks for checking it out!
Rahkshi8000,
Thank you very much!! I'm pursuing a career in engineering or the scientific field, but first I must conquer highschool.

You seem to have the steps correct for solving for velocity, but you said you were solving for theta. The range equation solved for theta is used in the programming, while the range equation solved for velocity was used by me to calculate the velocity of the LEGO brick.
I solved for theta, which was used in the programming, by:
1. Multiplying both sides by "g"
2. Dividing both sides by v^2
3. Removing sine from one side by finding the arcsine of the other side (finding the arsine of one side is the same as finding the sine of the other)
4. Dividing both sides by 2
The picture shows the equation solved for theta:
I also needed to solve for v (velocity), which allowed me to calculate the velocity of the LEGO brick:
1. Multiplying both sides by "g"
2. Dividing both sides by "sin(2θ)"
3. Finding the square root of both sides
This picture shows the equation solved for velocity:

Indeed, it was no coincidence that I picked a 45 degree angle for finding the velocity of the LEGO brick.

In fact, before I even learned about the range equation in physics, I was using a formula that was made especially for cases in which you are always launching at 45 degrees. The equation is surprisingly simple, although it makes total sense that it can be reduced that much when theta isn't a factor. Check it out:
Multiplying both sides by g and finding the square root, you come up with: velocity= square root of g*d.
I'm assuming you don't have the NXT-G programming language used by most Mindstorms users... if you did, you can easily download my program and check it out. I can post a few pictures if you'd like.
Thanks again for your compliments and interest in my project. Not everyone knows enough in physics/math to understand my project to the amount I would like them to, so I enjoy explaining my project to those who do.

If you have any questions, or my explanation is too confusing, please let me know.
