If I ____ rich, I would help the poor.

The correct answer is "were".

The sentence would be: "If I were rich, I would help the poor."

Explanation:

• This is an example of a second conditional sentence, which is used to express hypothetical situations and their possible outcomes in the present or future.
• In second conditionals, "were" is used instead of "was" for all subjects (I, you, he, she, etc.) in formal or standard usage.
• The structure of a second conditional is: If + past simple, ... would + base verb.

So, the complete sentence is: "If I were rich, I would help the poor."