1. Complete the table to summarize what you know about each engineer's conjecture: (2 points: 1 point for each row of the chart) Engineer
Conjecture

Natalie

Emma

2. Analyze the conjectures. Who do you think is correct, and why? (1 point)

Analyzing the Data
3. Here is a picture of the bridge truss, and the given information:

Fill out the two-column proof to prove that BED BEF. You may not need to use all the rows. (5 points)
Statement
Reason

4. State how you know that BDF is an isosceles triangle. (2 points)

5. Using the previous problem, fill out the two-column proof that ABD CBF. You may not need to use all the rows. (5 points)
Statement
Reason

Making a Decision
6. Are the truss triangles ADB and BFC congruent? Which postulate did you use for your proof? Which engineer was correct? (1 point)

7. Why do you think triangular structures are so stable? (2 points)

8. Here is a sketch of a Pratt truss, patented in 1844 by two Boston railway engineers, Caleb Pratt and his son Thomas Willis Pratt.

Name two triangles from the Pratt truss in the illustration that you would expect to be congruent. (2 points)