Australia is 8.4 times larger than Nigeria.
Area: 7,741,220 km2 World Factbook
Population: 22,507,617 (July 2014) World Factbook
Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the world's sixth-largest country by total area. Wikipedia
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