Let ABC be a triangle and let D be a point on the segment BC such that AD=BC. \\
Suppose ∠CAD=x∘,∠ABC=y∘ and ∠ACB=z∘ and x,y,z are in an arithmetic progression in that order where the first term and the common difference are positive integers. Find the largest possible value of ∠ABC in degrees. geometrytrig basharithmetic sequenceIOQM