Convert your feet to inches. So 8 times by 12 = 96 inches if you have 3/4 of the board used. 3/4= .75 if you were to times 96 by .75 = 72 inches. So you used 72 inches and you have 24 inches left
now do 1/3= .33 times .33 by 24= 8 8 inches is how long you would give to Anthony's brother.
