Jack cut a piece of wood that was 8 feet long into two pieces. One piece is three times as long as the other. How long is the shorter piece of wood?

Let the length of the shorter piece of wood be ( x ) feet. Then, the longer piece is ( 3x ) feet. Together, they add up to 8 feet, so the equation is ( x + 3x = 8 ). Solving this gives ( 4x = 8 ), so ( x = 2 ). Thus, the shorter piece of wood is 2 feet long.