How did Rhode Island become a state?

The state of Rhode Island was one of the original colonies. It was admitted into the union on May 29, 1790. The original 13 colonies were admitted into the Union upon ratification of the Constitution. There was probably had a controversy of letting them in the union. Rhode Island was the first of the thirteen colonies to declare independence from the British Rule and it was the last state approved from the U.S. Constitution. 

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When did Rhode Island become a state?

It became a state May 29, 1790. Rhode Island is the 13th state, and is also the last of the 13 colonies to be approved from U.S. Constitution.