Constructing a triangle with a compass


Materials:
compass
ruler
protractor
pencil
paper

What is a Triangle?
A triangle is a closed plane figure that has three sides and three angles


triangle.gif

What is a compass?
Not a compass that tells you, north, south, east, west. It is a geometry compass that has nothing to do with directions. It allows you to measure and draw shapes. A math geometry compass is a device used to determine geometric direction. Usually consisting of a magnetic needle or needle(s) horizontally mounted or suspended and free to pivot until aligned with the earths magnetic field.
Compass2.jpg

Real Life

This picture is of the Regina Twin Towers.
This picture has to do with real life and our topic because the building is triangle and they could have used a compass to sketch this ides for this building.
twin_towers_in_Regina.jpg

How to construct a triangle with a compass.





1)Use a ruler to draw an 8 cm line for B and C
2)With a compass and the pencil point spread the compass 6 cm apart.
3)Place the compass point on B and draw an arc above B and C.
4)With the compass and pencil point place it 5 cm apart.
5)Place the pencil point on C and draw and arc above B and C. Make sure the arcs intersect.
6)Label the point of the intersection A.
7)Join A and C and join A and B using a ruler to ensure straight lines.
8)Measure the sides using a ruler and label the them with their measurement.
9) Then you must measure the degrees for each angle using a protracter and add them up to make sure they equal 180 degrees.
NOTE: *All triangles constructed with a compass has to equal 180 degrees or you have measured the degrees wrong.*
For an assignment do the example above and if you want a challenge follow these rules but create your own measurement so you can decide how big the triangle is.