Ezekiel 42:3, 19-20

One block of rooms overlooked the 35-foot width of the inner courtyard. Another block of rooms looked out onto the pavement of the outer courtyard. The two blocks were built three levels high and stood across from each other.

and the west side was also 875 feet. So the area was 875 feet on each side with a wall all around it to separate what was holy from what was common.