Proving Congruent Triangles: Side-Side-Side and Side-Angle-Side Theorem

In this lesson I will teach how to prove two triangles congruent by the SSS and SAS theorems.  The SSS theorem stands for Side-Side-Side and the SAS theorem stands for Side-Angle-Side.  Now the sides and angles we are talking about are those of two triangles we are trying to prove congruent.  Hence if two triangles have the exact side lengths (all sides) then we can use the SSS theorem to conclude they are congruent.  Likewise if two triangles have two sides and an angle that are the same measure we can use the SAS to prove them congruent.  In this lesson we are focusing on “proving” so we will be doing proofs.  As such you may want to review your notes on how to plan and write a proof or watch the video lesson on this topic over again.  Congruent triangles are very important in geometry so you need to practice to really master and understand these proofs. Good luck!