Given that the set of natural numbers continue in the triangular pattern shown below, find the sum of the 6th number in row 7 and the 9th number in row 10.

Note: Row 1 is the first row of the triangle.

$$1$$
$$2\space\space3\space\space4$$
$$5\space\space6\space\space7\space\space8\space\space9$$
$$10\space\space11\space\space12\space\space13\space\space14\space\space15\space\space16$$
$$...$$

My approach (horrible): I found the quadratic sequence $x^2-x+1$ which produced the median of each row. Keeping the median as a reference point, I then counted manually to find the numbers in each row.