I have tried using the formulae given for this question and couldn't figure out how to do it- anyone have any answers
It would be better that you post what you have done and place a link to the problem that you are asking in future. https://isaacphysics.org/questions/phys19_c2_q5?stage=all If you are asking the question (part E) in the link, have you done your conversion from m2 to mm2 correctly?