OfficeSupplies101 has all of the Drafting Tools and Templates for your creative needs. A Drafting Triangle is a precision drafting tool for drawing lines at specific angles, measured in degrees. A drafting triangle always has one right angle 90°. This makes it possible to put a triangle against a T-square to draw vertical lines. We have Triangles available in 30°, 60°, 45° or 90°. To draw a line with a Drafting Triangle, hold it firmly against the blade of the T -square or parallel rule with your opposite hand. Then draw a line by moving a pencil along the edge of the triangle.