First, it might be helpful to find the total amount that he needs.
8*12.5=100 inches
6*8.75=52.5 inches
9*6.25=56.25 inches
100+52.5+56.25=208.75 inches
Shawn needs at least 208.75 inches of wood.
By taking the 208.75 total inches and dividing by 72 inches (the length of each board), we find out that he needs 3 boards. Now some arrangements need to be made to figure out what pieces to cut from the boards. There are multiple different ways to cut the boards, but this is one possible solution:
5(12.5)+1(8.75)=71.25
5(8.75)+2(12.5)=68.75
9(6.25)+1(12.5)=68.75