The problem asks us to select all ratios that are equivalent to $12:3$.

1. Problem Description

The problem asks us to select all ratios that are equivalent to $12:3$.

2. Solution Steps

First, simplify the ratio $12:3$ by dividing both numbers by their greatest common divisor, which is

3. $12:3 = (12/3):(3/3) = 4:1$

Now, check each of the given ratios to see if they are equivalent to $4:1$.

* $4:1$ - This is already in the simplified form and is equivalent to $12:3$.

* $18:5$ - To check if this is equivalent to $4:1$, we can see if $18/5 = 4/1$. Since $18/5 = 3.6$ and $4/1 = 4$, these ratios are not equivalent.

* $16:4$ - We can simplify this ratio by dividing both numbers by their greatest common divisor, which is

4. $16:4 = (16/4):(4/4) = 4:1$

So, $16:4$ is equivalent to $4:1$, and therefore also equivalent to $12:3$.

3. Final Answer

The ratios equivalent to $12:3$ are $4:1$ and $16:4$.