∠AOC + ∠BOE = 70o∠BOD = 40o      ...(i)∴ ∠AOC = ∠BOD     [ शीर्षाभिमुख कोण ]∴ ∠AOC = 40°    ...(ii)अब, ∠AOC + ∠BOE = 70°⇒ 40° + ∠BOE = 70°⇒ ∠BOE = 70° - 40°⇒ ∠BOE = 30°= ∠COD + ∠BOD + ∠BOE= ∠COD + 40° + 30°समीकरण (i) और (ii) से∠COE + 40° + 30° = 180o ⇒ ∠COE = 110oप्रतिवर्ती∠COE = 360o - 110o =- 250o