how big is 1 acre in square feet
Acre The acre is a unit of land area used in the imperial and US customary systems. It is defined as the area of 1 chain by 1 furlong (66 by 660 feet), which is exactly equal to ​1⁄640 of a square mile, 43,560 square feet, approximately 4,047 m2, or about 40% of a hectare.
Land "Land mass" refers to the total surface area of the land of a geographical region or country (which may include discontinuous pieces of land such as islands). It is written as two words to distinguish it from the usage "landmass", the contiguous area of land surrounded by ocean. Earth's total land mass is approximately 148,939,063.133 km2 (57,505,693.767 sq mi) which is about 29.2% of its total surface. Water covers approximately 70.8% of Earth's surface, mainly in the form of oceans and ice formations.[19]