A furniture store purchases a lamp for a $125. S the store needs a 65% mark up on cost. What is the increase in the cost of the lamp after the market

The mark up on the cost of the lamp is 65% of $125, which is (65/100) * $125 = $<<65/100*125=81.25>>81.25.

Therefore, the increase in the cost of the lamp after the mark up is $81.25. Answer: \boxed{81.25}.