Help Students Visualize Overlapping Triangles

When teaching triangle congruence, overlapping triangles appear at some point.  I always teach students to draw the triangles separately before making any conclusions.  This activity/demonstration helps students create overlapping triangles and separate them to see the triangles individually.

First, fold one corner of a piece of paper to form a triangle.  Trace the triangle on the piece of paper.

Cut along the traced edges and cut along the fold.  How do you know that the two triangles are congruent?

Label the angles of the triangle.  Have students write a congruence statement.

Use the two triangles to create different shapes.  Have some of the shapes use overlapping triangles.  

See how many other shapes students can find with their congruent triangles.

This is a great activity to do before starting congruent triangles proofs!