The Strength of Triangles Project
Bridges, Windmills, and the Wright Brothers’ Wings
You have been given three pictures to analyze…
A bridge
A windmill
A plan for a flying machine
Read the directions for this three-part assignment completely and carefully.
Part I--IDENTIFICATIONS:
Using a ruler and protractor, identify all sets of congruent and similar triangles in each image. Use colored pencils
or crayons to identify/code sets of congruent and similar triangles (in other words, color code the ones that go
together in the same way; outline the ones that are similar to each other in the same color and then outline the
ones that are congruent to each other in the same color). You need to make some notation that identifies why they
are congruent/similar. For example, if you measured an angle and 2 sides to be the same (SAS) then mark which
sides and which angles are congruent for those two triangles. Be sure to consider all the different ways we can
prove triangles to be either similar or congruent when you are checking for these relationships (go back and use
your chapter 8 notes or textbook to help you). You will turn in all three colored/coded illustrations.
Part II--WRITING:
On a separate sheet of paper, type two paragraphs (double spaced) in which you describe in detail all the methods
that can be used to prove two triangles similar or congruent (one paragraph for each). Explain all the different
ways we learned how to prove that two triangles are congruent or similar. Then, at the end of each paragraph,
explain which methods you used in making your decisions in the three pictures and why you chose to use those
methods.
Part III—OBSERVATIONAL RESEARCH:
You are to locate three other examples of “objects” that are constructed with the strength of triangles in mind (no
bridges, windmills, flying machines, or the Eifel Tower allowed as your examples). You may find that a simple
observation of your daily surroundings provides you with examples, or you may want to turn to the internet
and/or your family for ideas. Either find a picture on the internet, take a picture of something you see using
triangles, or draw a picture of each of your three examples. Each picture is to be on a separate sheet of paper and
have a caption identifying what the object is and a typed description of how it uses triangles.
EXAMPLE FOR PART 1: