990:243

To simplify the ratio 990:243, we can divide both numbers by their greatest common divisor (GCD).

1. First, find the GCD of 990 and 243.

   • The prime factorization of 990 is \( 2 \times 3^2 \times 5 \times 11 \).
   • The prime factorization of 243 is \( 3^5 \).

2. The only common prime factor is 3. The lowest power of 3 in both factorizations is \( 3^2 \).

3. Therefore, the GCD of 990 and 243 is \( 9 \).

4. Now, divide both numbers by their GCD:

   • \( 990 \div 9 = 110 \)
   • \( 243 \div 9 = 27 \)

Thus, the simplified ratio of 990:243 is \( 110:27 \).