This is a 2 page Microsoft Word file. The first page focuses on the definitions of opposite, between, and included by. The second page focuses on how to use a congruent statement to mark parts of triangles.
This is a worksheet I use in geometry before starting proofs of congruent triangles. It helps to really nail down common definitions that students will see when writing two-column proofs.
It also helps students learn how to mark congruent parts in both triangles.