Answer:
75°
Step-by-step explanation:
∠DGF = 2* ∠DEF
10x + 50 = 2(9x - 15)
10x + 50 = 18x - 30
50 = 18x - 30 - 10x
50 = 8x - 30
8x - 30 = 50
8x = 50+30
8x = 80
x = 80/8
x = 10
∠DEF = 9x - 15
= 9*10 -15
= 90 - 15
= 75°
