Technical Graphics - The Basics - Angles

It is very important to be able to draw angles in Technical Graphics. With your set squares sitting on your T-square you can four commonly used angles. These are 30°, 45°, 60° and 90°. You can see these below.
30°
45°
60°
90°
These are the basic angles and are easy to create using the set squares in the different orientations shown. Always make sure that the T-square is flush with the side of the drawing board and that the set squares are flush with the T-square.

Named Angles

Acute Angle

This is any angle which is between 0° and 90° exclusive.

Right Angle


This is an angle which is exactly 90°.

Straight Angle

This is an angle which is exactly 180°.

Obtuse Angle

This is an angle which is between 90° and 180° exclusive.

Reflex Angle

This is an angle which is greater than 180°.

Exercise