Partially Magic Squares

1. Place the numbers 1-9 into a 3x3 grid, such that the four sides and the two diagonals each have the same sum (greater than 15.) What is the number in the center of the grid?
2. Disregarding rotations and reflections, find all partially magic squares which use the numbers 1-9 and in which at least six lines of three numbers have the same sum (other than 15).

Source: Original.