Let ABC be a triangle and let a,b,c be the lengths of the sides BC,CA,AB respectively. Consider a triangle DEF with the side lengths EF=au, FD=bu, DE=cu. Prove that ∠A>∠B>∠C implies ∠A>∠D>∠E>∠F>∠C. inequalitiesgeometry proposedgeometrygeometry unsolved