How to display the tv value of a context resource in a snippet?

Question

PHP

So I get the data of a specific tv in the snippet.
$modx->resource->getTVValue('weneed');
full code and purpose of the snippet (calculate percentages):

<?php
$priceHave =  $modx->resource->getTVValue('wehave');
$priceNeed =  $modx->resource->getTVValue('weneed');
$procent=$priceNeed/100;  
$result=$priceHave/$procent;
echo round($result,2);

The problem is that it works only on the main page, and does not count on other pages for obvious reasons.

Answer 1

$resource = $modx->getObject('modResource', $resourceId);
$priceHave =  $resource->getTVValue('wehave');
$priceNeed =  $resource->getTVValue('weneed');
......