Answer:
 ∠D = 30°
Step-by-step explanation:
From the diagram; 
 DF = FE
 The diagram is that of an isosceles triangle in which two sides are equal in the figure. 
 Since DF = FE; 
 ∠E = ∠D because they are the angles facing the equal sides
Since ∠E = 30°; 
  ∠D = 30°