Can you arrange the numbers from 1 to 9 on a tic tac toe board in a manner that the numbers in each row, column and diagonal adds up to 15. Remember that you have to use all the 9 numbers and thus you cannot repeat.

In the image you can see some random number series.
But there is a pattern to the numbers.
Can you identify the pattern and
find the number that will replace the question mark symbol ?