Answer
$\frac{200 adults}{450 children}=\frac{4 adults}{9 children}$
Work Step by Step
We are given that 200 adults is to 450 children as 4 adults is to 9 children. In order to write this as a proportion, we can write both relations as fractions.
200 adults is to 450 children can be written as $\frac{200 adults}{450 children}$
4 adults is to 9 children can be written as $\frac{4 adults}{9 children}$
Next, we can set both fractions equal to each other, which gives us a proportional relationship.
$\frac{200 adults}{450 children}=\frac{4 adults}{9 children}$
Since the units in the numerators and denominators are different, we do not simplify any further.