



 
Cristina, No, with angels the traditional question is how many can dance on the head of a pin. If you mean angles (as Pope Gregory might have put it, "non angeli sed anguli") then every pair of rays determines two angles, one ordinary and one reflex (or both straight). If you are only interested in the nonreflex angle  and if we assume no two rays to be opposites  then the answer is the same as the number of pairs of distinct rays, n(n1)/2. If reflex and straight angles are also acceptable the answer is twice that and we can drop the assumption. Good Hunting!  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 