# Sample Proof on Triangle Congruence Part 3

Recall that for real numbers a, b, and c are real numbers, if $latex a = b$ and $latex b = c$, then $latex a = c$. This is called Transitive Property of Equality. This is also the same with congruence. If $latex A$, $latex B$, and $latex C$ are polygons, and if $latex A$ is congruent to $latex B$, and $latex B$ is congruent $latex C$, then $latex A$ is congruent to $latex C$. This is called the Transitive Property of Congruence. We will use this to prove the following problem.

Given: $latex \overline{BE} \cong \overline{DC}$ and $latex \overline{BD} \cong \overline{CA}$.

Prove: $latex \triangle DBE \cong \triangle CAB$.

Proof

It is given that $latex \overline{BE} \cong \overline{DC}$.

Now, by reflexive property, that is a segment is congruent to itself, $latex \overline{BD} \cong \overline{BD}$.  Continue reading

# Sample Proof on Triangle Congruence Part 2

This is the second part on a series of posts on worked proofs in Triangle Congruence. In this post, we prove another problem.

Given: $latex \overline{AB}$ and $latex \overline{CD}$ bisect each other at $latex E$.
Prove: $latex AD \cong BC$  Continue reading

# Sample Proof on Triangle Congruence Part 1

We have discussed triangle congruence and in this series, we are going to use the congruence theorems in order to prove that two triangles are congruent.

Given

$latex \overline{AB} \cong \overline{AE}$
$latex \overline{AC} \cong \overline{AD}$

Prove
$latex \overline{BD} \cong \overline{EC}$

Proof

We can see that there are two overlapping triangles: triangle $latex ADB$ and triangle $latex ACE$. Continue reading