ABCD is a cyclic quadrilateral whose diagonals intersect at a point E. If ∠DBC=80∘ and ∠BAC=40∘, then find ∠BCD.
ABCD is a cyclic quadrilateral whose diagonals intersect at a point E. If ∠DBC=70∘ and ∠BAC=30∘, then find ∠BCD. Further, if AB = BC, then find ∠ECD.