What happens to the dollar price that a U.S. (a) importer pays and (b) exporter receives if prices are agreed in euros and the dollar then

What happens to the dollar price that a U.S. (a) importer pays and (b) exporter receives if prices are agreed in euros and the dollar then appreciates by 10 percent with respect to the euro?

If the above situation occurs as mentioned then for a importer the dollar becomes more lessvaluable for importer as in most likelihood case he has to pay his suppliers in other currency sayEuro...