Congruent Triangles Flashcards

All 6 cards in this deck

What are the four congruence criteria for triangles?

SSS, SAS, ASA and RHS.

What does the congruence criterion RHS stand for?

Right angle, Hypotenuse and one other Side equal in both triangles.

For the criterion SAS, where must the equal angle be?

Between (included by) the two pairs of equal sides.

True or false? Two sides and a non-included angle (SSA) prove two triangles are congruent.

False. SSA is not a congruence criterion — the only exception is RHS, where the angle is a right angle.

What are the steps to prove two triangles are congruent?

e.g. prove $\triangle ABC \equiv \triangle DCB$ given $AB = CD$ and $\angle ABC = \angle BCD$

1. State three equal pairs with reasons: $AB = CD$ (given), $\angle ABC = \angle BCD$ (given), $BC$ common.
2. Name the criterion: SAS.
3. Conclude: $\triangle ABC \equiv \triangle DCB$.

Once you have proved two triangles are congruent, how do you show two lengths are equal?

State that corresponding sides of congruent triangles are equal.
e.g. $\triangle ABC \equiv \triangle DCB$, so $AC = BD$.