If a particle is deflected by 0.01 in each collision, about how many collisions would be necessary

If a particle is deflected by 0.01º in each collision, about how many collisions would be necessary to produce an rms deflection of 10º? (Use the result from the one-dimensional random walk problem in statistics stating that the rms deflection equals the magnitude of the individual deflections times the square root of the number of deflections.) Compare this result with the number of atomic layers in a gold foil of thickness 10^-6 m, assuming that the thickness of each atom is 0.1 nm = 10^-10 m.