Allow for drawing on figures for math problems

I feel as if it would be extremely beneficial for those practicing for the SAT on Khan Academy to be able to draw and mark up the figures provided in order to better mimic what they might do on test day. Personally, when working with problems involving geometry and trigonometry, I find it almost impossible to figure out the solution without drawing on the original figure. Since I cant take a pen to my computer screen, I m forced to redraw the figure myself, however I am a atrocious at drawing and I end up confusing myself more. Allowing this feature would greatly assist all of us visual problem solvers.