Answer:
Prometheus did two things to anger Zeus.
Firstly, he tricked him into requiring a lesser sacrifice from man.
Secondly, he stole fire from Zeus.
Step-by-step explanation:
When Zeus required the sacrifice of animals to himself and other gods, Prometheus proposed a bargain to which Zeus agreed. He offered Zeus two possible sacrifices to choose from, one which looked appealing but was in fact merely disguised animal bones and one which appeared less appetising but was in fact the best meat. Zeus chose the most appealing in appearance as the sacrifice to be. When he learned of the deception and his ensuing mistake, in anger he confiscated fire from man. That is when Prometheus stole the fire to restore it to humanity, further angering Zeus.