Answer: D.) SAS
Step-by-step explanation:
SAS congruence postulate says that if two sides and the included angle of a triangle are congruent to corresponding two sides and the included angle of other triangle then we say the two triangles are congruent.
In the given proof , in ΔABD and ΔACD
[tex]\overline{AB}\cong\overline{AC}[/tex] [side] (given)
[tex]\overline{BD}\cong\overline{CD}[/tex] [side] (given)
[tex]\angle{B}=\angle{C}[/tex] [included angle] (Base angles of isosceles triangles are congruent.)
So by SAS congruence postulate ΔABD ≅ ΔACD.
