Uchburchakda burchaklar

△ABC da $\angle BAC = 40^{\circ}$ berilgan. $AB$ uzaytmasi $BD$ bo‘lib, $\angle ABD = 120^{\circ}$ (tashqi burchak). $\angle ABC$ va $\angle ACB$ ichki burchaklar bo‘lsin. $\angle ACB$ ning o‘lchamini toping. Uchburchakning ichki burchaklaridan ikkitasi $80^\circ$ va $50^\circ$ ga teng bo'lsa, uning 3-ichki burchagini toping. Uchburchakning ichki burchaklaridan ikkitasi $70^\circ$ va $80^\circ$ ga teng bo'lsa, uning 3-ichki burchagini toping. Uchburchakning ichki ikkita burchagi $70^\circ$ va $60^\circ$ ga teng bo'lsa, uchburchakning bu burchaklarga qo'shni bo'lmagan tashqi burchagini toping. Uchburchakning ichki burchaklari $3:2:1$ nisbatda bo'lsa, uning eng katta tashqi burchagini toping. Uchburchakning ichki burchaklari arifmetik progressiyani tashkil qilsa, uning kattaligi bo'yicha o'rtacha burchagini toping.