search for: uneuqal

I need to make a plot illustrating main characterisitig of river drainage data. For this I have 2 questions: how can I rotate a histogram -90? (or 270?) (like the horizontal=TRUE with plot)? how can I use split.screen to produce 3 plot with uneuqal size (1/5, 2/5, 2/5 of the screen width)? thank you very much in advance for your help fabian