To simplify the fraction \( \frac{1287}{1225} \), we first find the greatest common divisor (GCD) of the two numbers.
Upon checking, we see:
- The prime factorization of 1287 is \( 3 \times 7 \times 61 \).
- The prime factorization of 1225 is \( 5^2 \times 7^2 \).
The common factor between the two numbers is \( 7 \).
Now we can divide both numbers by their GCD (7):
\[ \frac{1287 \div 7}{1225 \div 7} = \frac{183}{175} \]
So, the simplified form of \( \frac{1287}{1225} \) is \( \frac{183}{175} \).