Drawing a plane to fill ofCamera viewport

I don’t actually have to do this, but it’s question I don’t know the answer to that will help me with a more complicated thing.

I have an ofcamera with fov of 30, it’s viewport is taking up the entire screen, 1024*768. If I try to draw a plane using these dimensions, I need to set the z value to -1415 (x and y will be 0,0) for the width to fill the screen but the height doesn’t quite fill at the same time.