Constructing different angles and shapes
In this lesson, we will look at constructing different angles and shapes using a compass and a straight edge.
- A 90° angle can be obtained by constructing a perpendicular bisector.
- A 45° angle can be obtained by bisecting a 90° angle.
- A 22.5° angle can be obtained by bisecting a 45° angle.
- A 60° angle can be obtained by constructing an equilateral triangle.
- A 30° angle can be obtained by bisecting a 60° angle.
- A 15° angle can be obtained by bisecting a 30° angle.
Example: The figure shows a point A on a straight line. Construct an angle of 45° at point A.
Solution: Construct a 90° angle, and then construct an angle bisector to obtain a 45° angle.
The following video shows
- how to bisect a line
- how to bisect an angle
- how to construct a right angle
- how to construct a 60° angle
- how to construct a hexagon
The following video shows
- how to construct a 120° angle
- how to construct a 45° angle
- how to construct a 30° angle
- how to construct an equilateral triangle
- how to construct triangle given 3 sides using compasses
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