Print the triangles in color on cardstock and laminate. Each student will need only one triangle.
The triangle works like a stoplight. As the teacher asks a question related to the learning target(s), the student will hold up one vertex color to show their understanding of the material.
For example, the teacher might ask "Can you identify the types of angles formed by parallel lines?" The student would hold up the green vertex showing that "hey, I get it!" or he/she might hold up the red vertex showing "I need more help!", etc.