This worksheet is about formal proof.

You can use the previously covered conditions for congruency in triangles, i.e. SSS, SAS, AAS, RHS to justify your proof.

Example

Prove that the triangles ADC and ABC in the following rectangle ABCD are congruent.

Use the conditions SSS, SAS, AAS, RHS to justify your proof.

Answer

Proof

AD = BC and DC = AB (as opposite sides of a rectangle).

AC is a common side of both triangles.

Condition SSS is satisfied.

So triangles ADC, ABC are congruent.