## Unit Focus

The Art of Triangles focuses on the special qualities of the four types of triangles:

- Right triangles
- Isosceles triangles
- Obtuse triangles
- Acute triangles

The project addresses priority Common Core Standards for Units 1 and 2, Traditional Geometry, and Unit 5, Integrated Geometry.

It also focuses students on Mathematical Practice 3 (Construct viable arguments and critique the reasoning of others), Mathematical Practice 5, Use appropriate tools strategically, and Mathematical Practice 7 (Look for and make use of structure).

You can explore the CCSS here.

In addition, students will practice using online technologies and other resources for geometry. If you want to review the project outcomes again, go back to the Overview of Assessment.

## Timeline & Duration

3 weeks, based on approximately 5 hours of class time per week

Project Rating: Intermediate

## Critical Area

In previous grades, students were asked to draw triangles based on given measurements. They also have prior experience with rigid motions: translations, reflections, and rotations, and have used these to develop notions about what it means for two objects to be congruent. In this unit, students establish triangle congruence criteria, based on analyses of rigid motions and formal constructions. They use triangle congruence as a familiar foundation for the development of formal proof. Students prove theorems—using a variety for formats—and solve problems about triangles, quadrilaterals, and other polygons. They apply reasoning to complete geometric constructions and explain why they work.