There are only 3 lenses. 50, 75 and 150mm. Acording to mamiya they are 28, 42 and 82mm in 35mm equivalents. Altough you must rememeber that the format is 1:1 and not 2:3 as in 35mm so even if the diagonals are close in their mesurment, perpective is diferent. To get a good idea of what it looks like, take a photo horizontally, then vertically, put one over the other and fill the corners in your imagination, that would be the covarage you get on 6x6 with the same focal (more or less).
I found the 75mm to be a perfect all around lens, to the point I never used the 50 or 150 when I had them. The quality of all of them is beyon any doubt, just great. And you have all the framlines in the VF, unlike the mamiya 7.