The TechnoArt Set-Square Set is a must have for technical drawing collection.

The TechnoArt Set-Square Set is a must have for technical drawing collection.

The TechnoArt Set-Square Set is a must have for technical drawing collection.

TechnoArt Set-Square with cutout triangle.

TechnoArt Set-Square with cutout triangle.

TechnoArt Set-Square with cutout triangle.

TechnoArt Set-Square with cutout triangle.

TechnoArt Set-Square with cutout triangle.

TechnoArt Student 4-Piece Set-Square set.

TechnoArt Set-Square with cutout triangle.

TechnoArt Student Protractor and Set-Square combination tool.

TechnoArt Blackboard Set-Squares are a welcome addition to any classroom.

TechnoArt Blackboard Set-Squares are a welcome addition to any classroom.

Made from a strong, clear moulded plastic, this 180° Protractor from Jakar is divided into half degrees for more precise angles. It has an open centre to allow you to grip it more easily and measures 150mm (6inches) across.

This transparent plastic Set Square is perfect for students, architects and designers. It is a right-angled triangle with two interior angles of 45 degrees, and features a mm scale on one of its sides.

This transparent plastic Set Square is perfect for students, architects and designers. It is a scalene triangle with angles of 90, 60 and 30 degrees, and features a mm scale on its longest side.

Perfect for designers and architects, this adjustable set square is made of clear 3.5mm thick Plexiglass and is great for drawing and measuring angles. It consists of a large set square with a hypotenuse (longest side) measuring 25cm. The hypotenuse is mounted on a bolt and an arc scale, so that it can be swung out from the rest of the set square; this allows the set square to function as a protractor.The hypotenuse can be fixed in any position on the arc scale or left unfastened so that different angles can be measured. The arc scale runs from 0 to 45 degrees and 90 to 45 degrees. It bears 1 degree and 1/2 degree increments.