Trig River

Very neat hands-on activity where students learn about and use a right triangle to determine the width of a pretend river. Includes teacher notes, worksheets, and pre-assessment and post-assessments. The student will use appropriate trigonometric ratios to solve contextual problems.

Weblink address (URL): 
Trig River

Standards & Objectives

Learning objectives: 

After this activity, students should be able to:

  • Use right triangle trigonometry and angle measurements to calculate distances
  • Convert from US customary to metric units
  • Perform averaging and comparison of numbers
  • Explain how engineers use trigonometry and other mathematical relationships to estimate distances

Lesson Variations

Blooms taxonomy level: 
Applying
Extension suggestions: 
Interdisciplinary opportunities: 

Engineering Connection
Sometimes engineers cannot directly measure an object's size or distance because it would take too much time, or it is physically impossible (a tape measure to find the distance from the Earth to Pluto?). Instead of actually measuring a size or distance, engineers use trigonometry and other mathematical relationships to estimate it very accurately.

Helpful Hints

Materials List

Each group should have:

  • Trig River Worksheet
  • protractor (or printed copy of the attached Paper Half Protractor)
  • 1 piece of string (6-inch long). Any long, very thin items could be substituted, such as spaghetti noodle, pipe cleaner, etc.
  • pencil
  • tape measure or meter stick (groups can share)

References

Contributors: 
Lisa Leach
Originator: 
Ayers Institute for Learning & Innovation