Answer:
∠C = 110
Step-by-step explanation:
∠AGC = ∠DGF as vertical, and
∠AGC = ∠DGF = 1/2(AC + DF)= 1/2(81 +59) = 1/2 *140 = 70
∠AGC + ∠DGF = 70 + 70 = 140
∠AGD + ∠FGC + ∠AGC + ∠DGF = 360
∠AGD + ∠FGC + 140 = 360
∠AGD + ∠FGC = 360 - 140
∠AGD + ∠FGC = 220
∠AGD = ∠FGC, as vertical, so
2*∠FGC = 220
∠FGC = 110
