Question 287195
the number of terms in a row is the same as the number of the row


so the cumulative number of terms through row "r" is ___ n = (r+1)(r/2) = (r^2 + r) / 2


290 = r^2 + r ___ 0 = r^2 + r - 290


use the quadratic formula to find r ___ then round up to the next integer
___ this should be the row containing 289


find n for the preceding row, and you will know the position of 289 in the row