We can’t obtain the least total surface area by arranging 12 cubes by side by side.
∴ A = 2(lb + bh + lh)
= 2(12 × 1 + 1 × 1 + 12 × 1)
= 2(12 + 1 + 12)
= 2 × 25 = 50 Sq. cm.
We can obtain the least total surface area by arranging 3 cubes by 4 cubes.
∴ A = 2(lb + bh + lh)
= 2(3 × 1 + 1 × 4 + 3 × 4) (∵ l = 3; b = 1; h = 4)
= 2(3 + 4 + 12)
= 2 × 19
= 38 Sq. cm.
