Tanzania is 2.5% larger than Nigeria.
Area: 923,768 km2 World Factbook
Population: 177,155,754 (July 2014) World Factbook
Nigeria, officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. Wikipedia
Area: 947,300 km2 World Factbook
Population: 49,639,138 (July 2014) World Factbook
Tanzania, officially the United Republic of Tanzania, is a country in East Africa in the African Great Lakes region. It is bordered by Kenya and Uganda to the north; Rwanda, Burundi and the Democratic Republic of the Congo to the west; and Zambia, Malawi and Mozambique to the south. Wikipedia