Question

how did the attack on Pearl Harbor cause the United States to enter World War II?

Answer 1

It's actually quite simple, Japan attacked Pearl Harbor, but they also were to declare war on the US shortly before the attack occurred. That failed and the attack occurred before the official declaration of war. A few days later Germany and Italy declared war on the USA as well.

Answer 2

Can you help with mine?

Answer 3

The US was staying out of the war. The US was isolationism which means not taking sides and not getting involved. Once Japan bombed Pearl Harbor the US couldn't stay out of the war any longer and had to become involved and attack back.