SSC CGL Model Paper 9

∠EBC = 60° [Equilateral Δ]
∠OBC = 45° [DB is diagonal]
∠EBO = 60 - 45 = 15
∠BEO = 60°
In ΔBEO,
∠BEO = 60°
∠EBO = 15° [∠EBC - ∠OBC]
∠BOE = 180° - 60° -15 ° = 105°
∠BOE = ∠DOC = 105°
∠BOC = 180° -105 ° = 75°