You could also use a band saw or a jigsaw (orbital saw). The jigsaw will work, but the trick is to use the finest tooth blade and sandwich the plastic between scrap pieces of plywood to keep the Plexiglas from chattering and cracking. Then take your time to cut slowly and at a steady pace until completed. This is how I cut Plexiglas acrylic sheets in the shop.
As always, try this method or any method on a scrap piece of plastic to see if it works.