Please forgive the decimals! I wasn't really awake yet! I guess to simplify, the easiest formula I could come up with was:

a = b*SinA/SinB

a = Distance from Center of TV (Reference Point)to Center of Speaker
A = Angle for Speaker Placement divided by two (22.5deg - HT, 30deg - Music)
b = Distance from Seated position to TV (Reference Point)
B = Angle opposite b (67.5deg - HT, 60deg - Music)

It's weird what things you do to fill your time when the company's computer system crashes for 3 days.

Mike