5.(2023•普陀区校级模拟)已知点OOO为ABCABCABC的外心,且AO→⋅AB→+BO→⋅BC→<CO→⋅CA→\overrightarrow{AO}\cdot \overrightarrow{AB}+\overrightarrow{BO}\cdot \overrightarrow{BC}<\overrightarrow{CO}\cdot \overrightarrow{CA}AO⋅AB+BO⋅BC<CO⋅CA,则ΔABC\Delta ABCΔABC为((( )))