lol im clueless when it comes to measurements. 45 by 50 ..yup maybe a terry square size??
get out a ruler and work it out
yup you just cut it the size you want - rectangles are easiest.
if you look on cloth nappy site that sell precut packs of liners (like say bubblebubs) i think you would pay that for a pack of 3 - 5.
my liners are roughly 10cm by 20cm...id imagine you could make more doing it this way for cheaper??