5 ft = 5 * 12 in = 60 inches Four consecutive even numbers are: x, x + 2, x + 4, x + 6 x + x + 2 + x + 4 + x + 6 = 60 4 x + 12 = 60 4 x = 60 - 12 4 x = 48 x = 48 : 4 x = 12 Answer: Those shelves should be: 12, 14, 16 and 18 inches long. Verification: 12 + 14 + 16 + 18 = 60 in = 5 ft.