Solve on paper please

A particle accelerated by a potential difference enters a velocity selector that consists of perpendicular magnetic and electric fields. The particle travels straight when the magnetic field is 0.400 T and the electric field is 6.30 x 10 V/m. When the electric field is turned off, a sensor determines that the radius of the particle's path is 4.11 cm. a. What is the charge-to-mass ratio of this particle? b. Calculate the charge-to-mass ratios of an alpha particle, an electron, and proton. Identify the particle used in the experiment from the calculations. i. alpha particle ii. Electron iii. proton masses