The distance around a figure is called as Perimeter of that figure. For example, rectangle perimeter is 2(L+B) and where as perimeter of square is '4S'.
1, 2, 5 are figures that have patterns formed from four lines curved in a concave direction. 3, 7, 8 are figures that have patterns formed from four lines curved in a convex direction. 4, 6, 9 are figures that have patterns formed from these straight lines.