First of all let's consider triangle CDE
∠C + ∠D + ∠CED = 180° [Angle sum property]
43 + 35 + ∠CED = 180°
78 + ∠CED = 180°
∠CED =180- 78 = 102°
∠CED = ∠BEA [Vertically opposite angels are equal]
In Triangle ABR
∠A + ∠B + ∠BEA = 180° [Angle sum property]
∠A + 18 + 102 = 180°
∠A + 120 = 180°
∠A = 180 - 120
∠A = 60°
Therefore, m∠A = 60°
