
triangle, set square
:''In
American English, a set square is an alternative name for a
T-square.''
A 'set square' or 'triangle' (
American English) is an object used in
technical drawing, with the aim of providing a
straightedge at a particular
planar angle to a
baseline.
The most simple form of set square is a triangular piece of transparent
plastic with the centre removed. More commonly the set square combines this with a
ruler and a half circle
protractor, like on the picture. The outer edges are typically
bevelled. These set squares come in two usual forms, both
right triangles: one with 90-45-45 degree angles, the other with 30-60-90 degree angles. They are often purchased in packs with
protractors and
compasses.
Less commonly found is the adjustable set square. Here, the body of the object is cut in half and rejoined with a
hinge marked with angles. Adjustment to the marked angle will produce any desired angle up to a maximum of 180°.
See also
★
Polydrafter
★
Special right triangles