|
 |
In geometry,
constructions utilize only two tools
- the straightedge
(an unmarked ruler)
and the compass.
Never draw freehand when doing a construction! |
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
|
|
Each
construction is developed separately in the following web
pages.
Several videos showing the actual constructions are included.
|
|
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.
| 
