Either the pattern is shown incorrectly, or the question is asked incorrectly.
With the pattern as shown in the given URL, the "rows" are DIAGONAL rows.
Perhaps it is easier to see what the question is if we write the array of numbers so that the rows are horizontal:
row #
1 1
2 2 3
3 6 5 4
4 7 8 9 10
5 15 14 13 12 11
6 16 17 18 19 20 21
7 28 27 26 25 24 23 22
... ...
... ...
It should be relatively easy to see the following from the pattern for row n:
If n is even, then the LAST number in the row in the n-th triangular number, and the numbers in the row are INCREASING left to right;
If n is odd, then the FIRST number in the row is the n-th triangular number, and the numbers in the row are DECREASING left to right.
We are to find the 9th number in the 19th row. The first number in the 19th row is the 19th triangular number, (19*20)/2 = 190, and in the 19th row the numbers are decreasing from left to right, so the 9th number in the 19th row is 190-8 = 182.
ANSWER: 182