Due To The Thickness Of The Chalk
…there may be a slight error in your calculations. That was Sister Elmer’s warning about doing blackboard geometry on the west side of Chicago in the ’60s, but that was a long time ago, and before white boards and this excellent plastic 30/60/90 triangle for classroom use. Graduated on the longer non-hypotenuse leg for 17” in 1/8” increments. Measures 17-3/8" x 10-1/8" with (4) magnets on the reverse and a removable 5” long plastic handle on the front. In yellow and black, from Helix®.