Circle d has diameter ef. the measure of ∠gdf = 55° what is the measure of eh? file: ///c: /users/student/desktop/capture. jpg

The complete question in the attached figure

we know that    

if ∠GDF = 55° 

then 
∠EDH is also 55° 

because
ED=DF=radius of a circle
GD=DH=radius of a circle
EH=GF

hence
if  ∠EDH=  55° ( central angle)
then 
arc EH is also  55°

the answer is
arc EH is 55°