Western Australia (Australia) is 29% larger than Mexico.
Area: 1,964,375 km2 World Factbook
Population: 120,286,655 (July 2014) World Factbook
Mexico, officially the United Mexican States, is a federal republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of Mexico. Wikipedia
Western Australia is a state occupying the entire western third of Australia. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Southern Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east. Wikipedia