$\"\"$

The proportion is $\"\"$ .

$\"\"$

Cancel common terms.

$\"\"$

Apply cross products property: If $\"\"$ where $\"\"$ then $\"\"$ .

$\"\"$

$\"\"$ .

Subtract 2r from each side.

$\"\"$

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

To check the solution, substitute the value of $\"\"$ in the proportion $\"\"$ .

$\"\"$

Cancel common terms.

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

The value of $\"\"$ .