In a football championship, 153 matches were played. Every two teams played one match with each other. The number of teams, participating in the championship is …….. .

Explanation

To solve the problem, we need to find the number of teams participating in a football championship where 153 matches were played, and each team plays one match against every other team.

### Step-by-Step Solution:

1. **Understanding the Problem**:
- We know that every two teams play one match against each other.
- If there are \( N \) teams, the total number of matches played can be represented as the combination of \( N \) teams taken 2 at a time, denoted as \( \binom{N}{2} \).

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