AB=AC⇒ΔABC-Isoscel( este o simpla observatie) AB+BC=130 cm AB-BC=20⇒AB=BC+20 BC+20+BC=130 2·BC=110 2BC=110 BC=55 cm AB+55=130⇒AB=130-55⇒AB=75 cm AB=AC⇒AC=75 cmPΔABC= AB+BC+AC PΔABC=75 cm+55 cm+75cm PΔABC=205 cm sper ca te-am ajutat..Coronita? Multumesc!