**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:**

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**Acute Angle:**This is an angle less than 90Âº

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

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

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**Right Angle:**this is angle 90Âº

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**Angle on a straight line:**the angle is 180Âº. It is also referred to as 'straight angle'.

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

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**Complementary angles**are two angles with the sum of 90Âº

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**Supplementary angles**are two angles with the sum of 180Âº

**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.

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