Approximately 3.3 inches of rainfall per year.
If central Pennsylvania received only one-third of the usual rainfall in a really dry year, it would be receiving 1/3 * the usual amount of rainfall per year.
In an average year,
Pennsylvania gets about the same amount of rainfall as a desert, which is typically defined as an area that receives less than 10 inches of precipitation per year.
Therefore, if central Pennsylvania received only one-third of the usual amount of rainfall in a really dry year, it would be receiving,
1/3 * 10 inches = approximately 3.3 inches of rainfall per year.
This amount of rainfall is significantly less than the average rainfall in Pennsylvania and would qualify as a desert if it persisted over a long period of time.
Hence, Approximately 3.3 inches of rainfall per year.
To know more about Average visit,
https://brainly.com/question/20118982
#SPJ4