Adjustable Triangle

8" Adjustable Triangle allows drawing of angles from zero to 90° with a steel screw knob that secures the triangle's position. Inner graduations on the arc give degrees of one angle while the outer row of figures gives the degrees of the complimentary angle. Triangle is transparent for easy viewing to the page, and it includes circular openings of 1/4", 1/2", 3/4" and 1".