http://helios.augustana.edu/~dr/203/probs/Set 1.pdf Scroll down to #11 for a picture. So I kind of understand the math. I am a little confuse though. So why is a divided by sqrt(2)? If this is a vector, then the center is really (a(sqrt(2)))/2 and the x component would be divided by sqrt(2) which makes the equation equal a/2. Can someone explain this? Is my math wrong?