What are the roles of the academic teachers to their students?

In an experiment done by scattering 5.5 Mev alpha particles on athin gold foil, students find that 10,000 particles are scatteredat an angle greater than 50 degrees. a) how many of these particleswill be scattered greater than 90 degrees? b) how many of theseparticles will be scattered between 70 and 80 degrees?

1. I know that N(theta)= 10,000
2. My book says the answers should be 2170 and 1347
3. My teacher told me that we do not need to use t,n,k, or e in theequation because they will cancel out.
4. I tried doing the problem the way my teacher told me to but Ican not seem to get the right answer.
5. Equation:N(theta)=([(Ni)(n)(t)]/16)((e^2)/(4pi*eo))[(z1*z2)^2/(r^2*k*sin(theta/2)^4))
6. becomes N(theta1)/N(theta2)=sin(theta2/2)^4/sin(theta1/2)^4
Please help :) greatly appreciated