Answer:
$88,000 
Explanation:
We know that 
The operating profit = Revenues - cost
                                   = $2,600,000 - $2,100,000
                                   = $500,000
If there is increase, so the operating profit would be 
= Revenues - cost
where
Revenues = $2,600,000 + $260,000
                  = $2,860,000
Cost = $2,100,000 + $172,000
         = $2,272,000
So, operating profit is 
= $2,860,000 - $2,272,000
= $588,000
So, the increase in operating profit would be
= $588,000 - $500,000
=  $88,000