Proving Congruence

Transformations and congruence

• It is true that rigid transformations produce congruent figures.
• That includes translations, reflections and rotations.
• It does not include dilations.

But when you are asked to prove or verify congruence...

• You must find the lengths of sides using the distance formula
• ...and make sure corresponding sides are the same length.
• You must also determine that corresponding angles have the same measure.

Is there an easier way?

• Yes, there is!
• There are five sets of criteria that prove triangles are congruent...
• Without having to find all six sides and all six angles of the two triangles.
• Stay tuned.... that is another lesson for another day!