Answer:
x = 16
measure of Arc(DE) = 167°
Step-by-step explanation:
Since the arc EFG make a straight angle, we can infer;
180° = Arc(EF) + Arc(FG)
180° = (x-3)° + (12x - 25)°
180° = 13x - 28
208 = 13x
16 = x
Arc GF and DE are vertical angles so if you find the measure of Arc GF then it's the same as measure of Arc DE
mDE = mGF
mDE = 12x - 25
mDE = 12(16) - 25
mDE = 192 - 25
mDE = 167°
Hope this helps!
