ABCD is a cyclic quadrilateral. If ∠BCD=100∘ and ∠ABD=70∘, then find ∠ADB.
Given that ABCD is a cyclic quadilateral such that∠BCD=100∘ and ∠ABD=70∘.
Since opposite angles of a cyclic quadrilateral are supplementary,
Consider △ADB, since sum of angles of a triangle is 180∘, we have