We have that Mark cuts the board with 12 feets length on 8 same pieces. So, we have to divide 12 by 8:

\(12/8=1.5\) feet is the length of one piece

Result: 1.5 feet is the length of one piece

\(12/8=1.5\) feet is the length of one piece

Result: 1.5 feet is the length of one piece