A highway from Heron to Brahmagupta - Albrecht Hess We give a simple derivation of Brahmagupta's area formula for a cyclic quadrilateral from Heron's formula for the area of a triangle. ✪ ✪ ✪ ✪ ✪ Link tải tài liệu: LINK TẢI TÀI LIỆU Theo LTTK Education