Respuesta :

calculista
we know that
The inscribed angle measures half of the arc it comprises.
so
∡BAY=BY/2------> 24/2------> 12°

angles YAC and BAY are complementary angles
∡YAC+∡BAY=90°
∡YAC=90-∡BAY-------> ∡YAC=90-12-----> 78°

the answer is
78°