Answer:
Givens
[tex]AB \cong AC[/tex]
[tex]\angle BAD \cong \angle CAD[/tex]
Prove
Line AD bisects line BC.
Now, the missins reasons are numeral 4 and 5.
4. [tex]\triangle BAD \cong \triangle CAD[/tex] 4. By SAS postulate.
SAS postulate states if two triangles has two pairs of corresponding sides congruent and the pair of corresponding angles between them are also congruent, then those triangles are completely congruent.
5. [tex]BD \cong CD[/tex] 5. By congruence of corresponding sides.
After we prove a congruence, we can make several congruent deductions of the rest of elements between those congruent triangle. In this case, we deduct that BD and CD are congruent because those triangles are congruent.
