# G.2.4 Lesson Summary

This activity is the first introduction to the criteria we need to show that 2 triangles are congruent. We are going to spend the next few weeks focusing on these ideas. No need to have this mastered today - just the idea that we can use 3 pieces of specific information to show 2 triangles are congruent.
Triangle Congruence Criteria Assertions: Our experiements today lead us to believe that these combinations of sides and angles will show 2 triangles are congruent: • Angle-Side-Angle (ASA) “Two angles and the included side.” • Angle-Angle-Side (AAS) “Two angles and the non included side.” • Side-Angle-Side (SAS) “Two sides and the included angle.” • Side-Side-Side (SSS) “All three sides.” • Hyptenuse-Leg (HL) "The hypotenuse and leg of a right triangle (so also a 90 degree angle)."
Sets of information that are not valid triangle congruence criteria Our experiments today showed us that these combinations of sides and angles will NOT show 2 triangles are congruent: • Side • Side-Angle • Side-Side-Angle (SSA) "Two sides and a non-included angle" (the easy way to remember this one is that it can make a bad word when the A is not between the 2 S's, but we choose to not write it in that order to be polite!) • Angle-Angle (AA) This one makes similar triangles!