**Geometrical construction** of lines involves the use of lines and angles to depict a shape or an object.

A* Line* is a mark or stroke long in proportion to its breadth, made with a pen, pencil, tool, etc on a surface.

A line can also be defined as a long thin mark made by a pen, pencil, marker, etc. **Types of angles: **

· **Acute Angle:** This is an angle less than 90º

·** Obtuse Angle:** this angle is greater than 90º but not more than 180º

· **Reflex Angle:** this angle is greater than 180º but not more than 360º

· **Right Angle:** this is angle 90º

· **Angle on a straight line:** the angle is 180º. It is also referred to as ‘straight angle’.

· **Angle that makes a revolution:** the angle is 360º or angle around a point. It is full rotation.

· **Complementary angles **are two angles with the sum of 90º

· **Supplementary angles** are two angles with the sum of 180º

**Questions: **

1. What does geometrical construction of lines involve?

2. What is a line?

3. Outline and clearly describe 5 different types of angles.

4. Outline the differences between acute, Obtuse and Reflex angles.

5. Why is 180° called a straight angle?

6. Differentiate between complimentary angles and supplementary angles.