IOM 2016, Блиц — Задача 37

Olympiad of Metropolises, Moscow. Blitz Contest, September, 5 · 5 септември 2016 г.

Условие

See figure.

Point MM is the center of the circle, BABA equals to radius of the circle, ∠CMD=78∘\angle CMD = 78^{\circ}.

Find ∠BFC\angle BFC.

Give the answer in degrees.

Circle with centre M; diameter line D–M extended beyond the circle to an external point A. Line from A through B (on the circle) to C (on the circle); segment BA and radius MC are marked equal. Chords CF and BF are drawn, F on the lower left of the circle. The angle CMD is marked 78° and the angle BFC at F is marked with a question mark.

Решение

Внимание: Непълно решение

В архива няма официално решение на тази задача.

Оригинал в Архива: blitz.pdf