400,000 sq m
Because the people said it means the Gate of Heaven ly peace for the Gates at the front.
A square has 4 sides that are of equal length. The area of a square is the length of one side multiplied by itself, or squared. So, to find the length from the area you must take the square root of...
If I do recall, the USA is currently 3.6 million square miles.
It's about as big as a large county in a midwestern state of the U.S.