$\"\"$

The word $\"\"$ 4 is to 12 $\"\"$ represents the expression $\"\"$ .

The word $\"\"$ as $\"\"$ means equal and its symbol $\"\"$ .

The word $\"\"$ n is to 3 $\"\"$ represents the expression $\"\"$ .

The word $\"\"$ 4 is to 12 as n is to 3 $\"\"$ represents the proportion $\"\"$ . $\"\"$

The proportion is $\"\"$ .

Multiply each side by 3.

$\"\"$

Cancel common terms.

$\"\"$ . $\"\"$

The value of $\"\"$ .