Type the correct answer in the box. Use numerals instead of words. If necessary, use / for the fraction bar. Find the missing number in this proportion.
9
=
18 32

Damon makes 20 cups of lemonade by mixing lemon juice and water. the ratio of lemon juice to water is shown in the tape diagram. lemon juice\text{lemon juice} lemon juice water\text{water} water how much lemon juice did damon use in the lemonade? cups