The diagonal point triangle revisited - Martin Josefsson We derive a formula for the area of the diagonal point triangle belonging to a tangential quadrilateral in terms of the four tangent lengths, and prove a characterization for a tangential trapezoid. ✪ ✪ ✪ ✪ ✪ Link tải tài liệu: LINK TẢI TÀI LIỆU Theo LTTK Education