Tolong bantu jawab ya kk terima kasih

∠A = 55°
∠C = 85°
∠a = n
∠a = 180 - (55 + 85)
     = 180 - 140
     = 40°
∠A = ∠c = 55°
∠a + ∠b + ∠c = 180
40 + ∠b + 55 = 180 
∠b = 180 - (40 + 55)
∠b = 180 - 95
∠b = 85°