The body of water would be the Baltic Sea. Three bordering countries could be e.g. Germany, Slovakia and Belarus. There are 7 countries bordering Poland in total. In addition to the ones I mentioned, it's also Czech Republic, Ukraine, Russia and Lithuania.
Germany lost, they lost to the Allies Russia was part of the Allies
"50 degrees and 70 degrees north latitude" describes a 'band' around the northern hemisphere that's 20 degrees wide and completely circles the globe. It includes all or part of ... -- Iceland -- Ireland -- England -- Scotland -- Wales -- Norway -- Sweden -- Denmark -- Finland -- France -- Belgium -- Netherlands -- Germany -- Czech Republic -- Poland -- Estonia -- Latvia -- Lithuania -- Ukraine -- Russia -- Kazakhstan -- Mongolia -- China -- USA -- Canada -- Greenland
Prussia is a country that was dissolved after World War II, so it is no longer on the maps. However, much of Eastern Europe was at one time or another part of Prussia and its many incarnations. If you are wondering about Prussia directly before it was dissolved, it would be between Germany and Poland on modern maps, and a bit on the coast of the Baltic sea where modern day Kaliningrad Oblast is now.
Estonia is just north of Latvia on the south west side of the Baltic Sea in the north eastern part of Russia, northwest of Poland.
Kaliningrad:(part of Russia) and Lithuania
The Enclave of Kaliningrad
Kaliningrad Oblast
Kaliningrad
Kaliningrad Oblast
Sweden, Denmark, Russia, Germany, Latvia, Lithuania, Estonia and Finland
That is Kaliningrad
The city's name is Kaliningrad.
The enclave of Kaliningrad
That is the Conclave of Kaliningrad
It was a Prussia - part of German land.
Because the victorious Allies of World War 2 wanted it that way that Prussia is part of Poland, Russia, and Lithuania.