you can just get a protractor from the school supplies section at the store. i had a new dear jane triangle ruler cut at the hardware store. then, to draw the 1/4" seam allowance marks, i used a sharp tool that i've had that engraves security marks/numbers on home products... i think it has a tiny diamond tip. i was pleased with my final product. if you go the route of having the hardware store cut your acrylic, call and ask if they can determine the angle for you... it will save you from trying to be very accurate with the protractor.