1, the height of the cuboid is constant, and (cuboid volume) is proportional to (bottom area);

The width of a cuboid is constant, and (volume) is proportional to (product of length times height);

The length of a cuboid is fixed, and (volume) is proportional to (side area-width × height).

2, ① (positive) ratio; ② (positive) ratio; ③ Out of proportion; (4) (positive) proportion; ⑤ Out of proportion.