Answer:
ΔAMD ≅ ΔCMD by Side Side Side (SSS) congruency rule
Step-by-step explanation:
Given that ΔABC is an isosceles triangle, with
≅ 
With BM as the median line from B to AC, we have;
∠ABM = ∠CBM
Also we have;
≅
- Reflexive property
Therefore, ΔABD ≅ ΔCBD Side Angle Side SAS condition of congruency
Therefore;
≅
Corresponding sides of congruent triangles are congruent CPCTC
≅
- AC is bisected by
where
= Median line
≅
- Reflexive property
Therefore, we have;
ΔAMD ≅ ΔCMD - Side Side Side (SSS) congruency rule