PQ/AB=16/12=4/3 QR/BC=20/15=4/3 PR/AC=28/21=4/3 PQ/AB=QR/BC=PR/AC => PQR подобен ABC S(PQR)/S(ABC)=(4/3)^2=16/9
PQ/ AB = QR/BC = PR/AC = 4/3
PQR : ABC = 4:3