Brent Spence Bridge

By Amy Dimmerling • Bethany Vice Bowling• Emma Massie

Grade Level	10th
Subject Area	Geometry
Duration	3 - 80 min class periods
Background Knowledge	1. Students must know basic geometry conjectures and theorems including but not limited to triangle similarities. 2. Students must know how to use scale factors 3. Students must be able to construct figures using a ruler and protractor.
Author	Amy Dimmerling, Bethany Vice Bowling, Emma Massie

Summary
This lesson requires the students to do the job of a steel fabricator for a truss bridge. The bridge used in this lesson is the Brent Spence Bridge in Cincinnati, Ohio. This bridge was divided into 8 different sections. Each group of students will be responsible for one section of the bridge. They will use their geometry skills to find all of the angles and lengths of each member of this truss in their section. The students will then scale down these members and create a scale drawing. From these drawing the students will build a scale model of their section of the bridge and then combine it with the other sections to create one large bridge.

Objectives
Students will: 1. Utilize the basic geometric conjectures and theorems to determine missing angles and member lengths 2. Use ratios to scale down their bridge section 3. Develop scaled drawings using their measurements 4. Construct at model of their bridge section

Materials Required
Handouts - Calculator - Ruler - Protractor Building Materials – Option 1 * 350 Wide Craft Sticks (like tongue depressors) * Drill * 7/16” Drill Bit * 200 – No. 4 Machine Screws & Nuts * Scissors * Tape * 50 – “L” brackets * 100 – Washers for No. 4 or No. 6 Machine screw Building Materials – Option 2 * 350 Wide Bract Sticks (like tongue depressors) * Scissors (one pair per group) * Binder Clip (Figure 1) * Wood Glue * 100 – No. 4 Machine Screws & Nuts * 50 – “L” brackets * 100 – Washers for No. 4 or No. 6 Machine screws

Ohio Standards

Mathematics

Geometry and Spatial Sense Standard

Grade 10
Construct congruent figures and similar figures using tools, such as compass, straightedge, and protractor or dynamic geometry software.

Grade 9
Apply proportions to solve problems involving missing lengths and angle measures in similar figures.

Grade 8
Determine and use scale factors for similar figures to solve problems using proportional reasoning.

Grade 7
Use proportions in several forms to solve problems involving similar figures (part-to-part, part-to-whole, corresponding sides between figures).