$\"\"$

52.5 is compared the 145. So, 52.5 is the part and 145 is the whole.

$\"\"$ (Percent proportion)

$\"\"$

Apply cross multiplication property: $\"\"$ , when $\"\"$ .

$\"\"$

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

$\"\"$ (Divide each side by 145)

$\"\"$ (Cancel common terms)

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

The 52.2 is $\"\"$ of 145.