Answer:
TRUE
Explanation:
≅ mens the triangles are congruent (the same arcs and the same sides in both). Basicaly it means they are the same exept its positon (can be mirrored or rotated)
So if ΔDEF is the same as ΔABC and the same as ΔMNO that maens ΔMNO must be the same as ΔABC
{ΔABC≅ΔDEF and ΔDEF≅ΔMNO} ⇒ ΔABC≅ΔMNO
And if ΔMNO is the same as ΔABC and the same as ΔPQR that maens ΔPQR must be the same as ΔABC
{ΔABC≅ΔMNO and ΔMNO≅ΔPQR} ⇒ ΔABC≅ΔPQR