Basic Constructions
https://www.youtube.com/watch?v=mKXqOklRytQ
In geometry, constructions utilize only two tools – the straightedge (an unmarked ruler) and the compass.
The Compass
Compasses come in a variety of styles. Become familiar with the compass you will be using before beginning your constructions.
Suggestions for working with a compass:
- Place several pieces of paper under your worksheet to allow the compass point to remain stable.
- Hold the compass lightly and allow the wrist to remain flexible.
- If you cannot manage to move your wrist when drawing circles, try rotating the paper under the compass.
The Straightedge
A straightedge is generally a clear plastic tool devoid of markings. It most often appears in the shape of a triangle. A portion of a straightedge is visible in the lower left corner of the picture on the left below.
If you do not have a straightedge, a ruler may be used. Just remember to completely ignore the markings on the ruler.
Basic Geometrical Constructions:
The basic constructions used in geometry include:
- copy a line segment
- copy an angle
- bisect a line segment
- bisect an angle
- construct perpendicular lines
- construct parallel lines
- construct isosceles triangle
- construct equilateral triangle
While the constructions listed above are considered the basic geometrical constructions, you should also be able to construct situations that require the use of these constructions.
Constructing Angle Bisectors
Constructing Triangles
