The U.S.-dollar-per-euro exchange rate was 0.8703 on Monday and 0.8807 on Tuesday. Did the euro depreciate or appreciate relative to the dollar? How much in percent did it appreciate or depreciate?

Think it through.

On Monday, one dollar could buy .8703 euros. On Tuesday it could by .8807. The dollar could buy more euros -- the value of the dollar went up. .8807/.8703= about a 1%+ increase