To determine which option is a proportion, we need to check if the two ratios in each option are equal.
A proportion is defined as an equation that states two ratios are equivalent.
Let's examine each option:
Option 1: \[ \frac{5}{6} = \frac{15}{18} \] To check if these fractions are equal, we can simplify both the right-side fraction: \[ \frac{15}{18} = \frac{15 \div 3}{18 \div 3} = \frac{5}{6} \] Since both fractions are equal, Option 1 forms a proportion.
Option 2: \[ \frac{5}{6} = \frac{20}{18} \] Check if these two fractions are equal by simplifying the right-side fraction: \[ \frac{20}{18} = \frac{20 \div 2}{18 \div 2} = \frac{10}{9} \] Since \(\frac{5}{6} \neq \frac{10}{9}\), Option 2 does not form a proportion.
Thus, Option 1 is a proportion.