So ∠ b = ∠ c = 30, ∠ bad = ∠ DAC = 60.
And because BD=BE, ∠ BDE = ∠ Bed = 75.
Because ∠ bed+∠ DEA = ∠ ade+∠ EAD+∠ DEA =180.
So ∠BED=∠EAD+∠DEA is 75 = 60+∠ ade, so ∠ ade = 15.
(2) Because FM divides DC vertically, DM=CM and DMF = 90.
So △ DNF △ CMFSO ∠ FDC = ∠ C = 30, that is ∠ ADF = 60, and ∠ DAC = 60.
So ∠ DFA = 60, so △ADF is a regular triangle.
(3) Because DM=CM, the AD of CM/DC=EM/AD= 1/2 is 4.
Sin∠B=AD/AB means AD/sin∠B=AB.
AD=4, sin∠B= 1/2, so AB=8.