Answer:
The measure of arc BG is 25°
Step-by-step explanation:
we know that
The measure of the inner angle is the semi-sum of the arcs comprising it and its opposite.
so
m∠DFC=(1/2)[arc CD+arc BG]
we have
m∠DFC=40°
arc CD=55°
substitute and solve for arc BG
40°=(1/2)[55°+arc BG]
80°=[55°+arc BG]
arc BG=80°-55°=25°
