Answer :

18 = 2·3·3

So possibles prisms are:

2×3×3

1×2×9

1×6×3

1×1×18

Therefore Quentin can make 4 different rectangular prism with 18 unit cubes.

Answer:

Quentin could built 3 different rectangular prism.

Step-by-step explanation:

Quentin could built by arranging the unit cubes in rows and columns.  Let us say  R units cubes are in a row  and  C unit cubes in a column.

R × C = 18 = 1 × 2 × 3 × 6 × 9 × 18

1.  R = 18    C = 1        This  prism is same as  if R = 1 and C = 18

2.  R = 9   C = 2              same if  R = 2,  C = 9

3.  R = 3    C = 6

So answer is 3.