9) Рис. 8.52. Найти: ∠BAD.

∠BED - внешний угол треугольника AED. ∠BED = ∠EAD + ∠ADE. ∠AED=60. ∠AED = ∠BEC => ∠BEC = 60. ∠BAD = 60/2 = 30°.