Final answer:
Texas joined the union as a state in 1845 after being an independent republic
Step-by-step explanation:
Texas joined the union as a state on December 29, 1845. However, before becoming a state, Texas was an independent republic. It declared independence from Mexico on March 2, 1836, and existed as the Republic of Texas until its annexation by the United States. This occurred during the presidency of James K. Polk, who signed a resolution for Texas' admission to the union.
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