Angles

An angle is the space formed between two straight lines meeting at a point called the vertex. Think of it like the corner where two walls meet in your classroom. Technical drawing requires you to construct different angle types accurately using only a compass and straightedge.

The main angle types you'll encounter are acute angles (less than 90 degrees), right angles (exactly 90 degrees), obtuse angles (between 90 and 180 degrees), and reflex angles (more than 180 degrees). Construction methods vary for each type. For example, constructing a 60-degree angle uses the properties of equilateral triangles, while bisecting angles—dividing them into two equal parts—involves drawing an arc from the vertex to create equal distances.

In Nigerian architecture, you'll see angles everywhere: the roof pitch of traditional Yoruba houses, the corner joints of furniture, and the layout of compound walls all depend on precise angle construction.