Dada uma P.G. finita qualquer com n elementos (a 1 , a 2 , a 3 ,...,a n ), temos

c.) Triangles ABD and CBD are congruent by the SAS Congruence Postulate.

Step-by-step explanation:

Line segment DB divides <ADC into two congruent angles. That is:

<ADB is congruent to <CDB

Segment DB of ∆ABD is congruent to segment DB of ∆CBD.

Also, Segment AD of ∆ABD is congruent to segment CD of ∆CBD.

This means two sides (DB and AD) and an included angle (<ADB) of ∆ABD are congruent to the corresponding two sides (DB and CD) and included angle (<CDB) of ∆CBD.

Therefore, by the SAS Congruence Postulate, ∆ABD is congruent to ∆CBD.