Launching a Projectile: What Angle for 1/8 Circumferential Radius?

[will3330]

This was on my exam today and I'm not sure if I was doing it right:

At what angle must a projectile be launched at so that the circumferential radius at the axel (top) is 1/8 the circumferential radius of the initial position.

This was all we were given (and I'm not posting my answer as it covers some weird logic).

What do you think about it.

 

[Andy Resnick]

I don't know what the phrase 'circumferential radius' means, and how it applies to projectile motion.