2 diagonals of a regular nonagon (a 9-sided polygon) are chosen.  What is the probability that their intersection lies inside the nonagon?
Question:
2 diagonals of a regular nonagon (a 9-sided polygon) are chosen.  What is the probability that their intersection lies inside the nonagon?
Answer:
Let's think step by step.

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\dfrac{14}{39}
2 diagonals of a regular nonagon (a 9-sided polygon) are chosen.  What is the probability that their intersection lies inside the nonagon?
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