In triangle ABC, where angle B is 100 degrees, angle C is 50 degrees, and
the lengths of sides BC, AC, and AB are denoted by a, b, and c
respectively. Prove that: (1) the area of triangle ABC = bc/4;
(2) Inradius ;
(3) .*This entry contributed by Sumith Peiris, Moratuwa, Sri Lanka. *