About Lesson
What is constructing triangles?
Constructing triangles is making an accurate drawing of a triangle with some information given.
To do this we need to use a pencil, a ruler and compasses.
E.g. Here is a triangle with sides , and constructed using a pencil, a ruler and compasses.
How to construct triangles given all three sides
In order to accurately construct a triangle given all three sides (SSS):
- Draw the base.
- Set compasses for the second side and draw an arc.
- Set compasses for the third side and draw an arc.
- Join up the intersection of the arcs.
How to construct triangles given two sides and the included angle
In order to accurately construct a triangle given two sides and the included angle (SAS):
- Draw the base.
- At one end point measure one angle.
- At the same endpoint draw an arc.
- Complete the triangle.
How to construct triangles given two angles and the included side
In order to accurately construct a triangle given two angles and the included side (ASA):
- Draw the base.
- At one end point measure one angle.
- At the other end point measure the second angle.
- Complete the triangle.
Exercise Files