$\"\"$

7 is being compared to 3500.

So,7 is the part and 3500 is the whole.

Let n represent the percent.

The percent proportion is $\"\"$ .

Apply cross product property of equality: $\"\"$ then $\"\"$ .

$\"\"$

$\"\"$ (Multiply: $\"\"$ ) $\"\"$

Apply division property of equality: Divide each side by 3500.

$\"\"$

$\"\"$ (Cancel common terms)

$\"\"$ (Divide: $\"\"$ ) $\"\"$

7 is 0.2 $\"\"$ of 3500.