about how much of its property did mexico lose during the mexican-american war
Mexican–American War Before the secession of Texas, Mexico comprised almost 1,700,000 sq mi (4,400,000 km2), but by 1849 it was just under 800,000 square miles (2,100,000 km2). Another 30,000 square miles (78,000 km2) were sold to the U.S. in the Gadsden Purchase of 1853, so the total reduction of Mexican territory was more than 55%, or 900,000 square miles (2,300,000 km2).[165]
Mexican–American War In 1845, newly elected U.S. President James K. Polk made a proposition to the Mexican government to purchase the disputed lands between the Nueces River and the Rio Grande river further south. When that offer was rejected, President Polk moved U.S. troops commanded by Major General Zachary Taylor further south into the disputed territory. Mexican forces attacked an American Army outpost ("Thornton Affair") in the occupied territory, killing 12 U.S. soldiers and capturing 52. These same Mexican troops later laid siege to an American fort along the Rio Grande.[6] Polk cited this attack as an invasion of U.S. territory and requested that the Congress declare war.