what are the major religions in eastern europe?

Pretty much Christian/Orthodox

we r studying this in school. roman cath, protestant, lutheran, christian

there's islam in those regions too

Mostly Orthodox or Roman Catholic and some Lutheran.
Russia, Ukraine: Orthodox,
Poland, Lithuania: Roman Catholic, Latvia
Lutheran: Latvia

On the other hand, the CIA World Factbook[6] geographically defines:

Central Europe: Austria, Czech Republic, Germany, Hungary, Poland, Slovakia and Slovenia
Eastern Europe: Belarus, Estonia, Latvia, Lithuania, and Ukraine
Southeastern Europe: Albania, Bulgaria, Bosnia and Herzegovina, Croatia, Serbia, Macedonia, Romania, Montenegro and part of Turkey
Russia is defined as a transcontinental country.

Belarus-Eastern Orthodox 80%, other (including Roman Catholic, Protestant, Jewish, and Muslim) 20% (1997 est.)
https://www.cia.gov/library/publications/the-world-factbook/geos/bo.html

Estonia-Evangelical Lutheran 13.6%, Orthodox 12.8%, other Christian (including Methodist, Seventh-Day Adventist, Roman Catholic, Pentecostal) 1.4%, unaffiliated 34.1%, other and unspecified 32%, none 6.1% (2000 census)
https://www.cia.gov/library/publications/the-world-factbook/geos/en.html

Latvia-Lutheran, Roman Catholic, Russian Orthodox
https://www.cia.gov/library/publications/the-world-factbook/geos/lg.html

Lithuania-Roman Catholic 79%, Russian Orthodox 4.1%, Protestant (including Lutheran and Evangelical Christian Baptist) 1.9%, other or unspecified 5.5%, none 9.5%
https://www.cia.gov/library/publications/the-world-factbook/geos/lh.html

Ukraine-Ukrainian Orthodox - Kyiv Patriarchate 19%, Orthodox (no particular jurisdiction) 16%, Ukrainian Orthodox - Moscow Patriarchate 9%, Ukrainian Greek Catholic 6%, Ukrainian Autocephalous Orthodox 1.7%, Protestant, Jewish, none 38%
https://www.cia.gov/library/publications/the-world-factbook/geos/up.html

There are about 17 countries in Eastern Europe; they vary considerably in religious affiliation. For example, Albania is 70% Muslim; Poland is 90% Roman Catholic and Macedonia is about 65% Orthodox, 33 % Muslim.

Catholic. . .Protestant. . .