What will be the total surface area of 5 cubes having side 3 cm.? If t

1.	What will be the total surface area of 5 cubes having side 3 cm.? If they are stocked one after one, then how much surface area will be decreased?
Answer» Total surface area of 5 cubes each of 3 side = 270 cm² If 5 cubes are joined one after one, then it becomes a cuboid whose length (l) = 3 cm. + 3 cm. + 3 cm. + 3 cm. + 3 cm. = 15 cm. Breadth (b) = 3 cm. Height (h) = 3 cm. ∴ Surface Area= 2 (lb + bh + hl). = 2 (15 x 3 + 3 x 3 + 3 x 15) = 2 (45 + 9 + 45) = 198 cm² ∴ Hence, surface area will be reduced and the difference = 270 cm² – 198 cm² = 72 cm²

What will be the total surface area of 5 cubes having side 3 cm.? If they are stocked one after one, then how much surface area will be decreased?

Answer»

Total surface area of 5 cubes each of 3 side = 270 cm²

If 5 cubes are joined one after one, then it becomes a cuboid whose length (l)

= 3 cm. + 3 cm. + 3 cm. + 3 cm. + 3 cm.

= 15 cm.

Breadth (b) = 3 cm.

Height (h) = 3 cm.

∴ Surface Area= 2 (lb + bh + hl).

= 2 (15 x 3 + 3 x 3 + 3 x 15)

= 2 (45 + 9 + 45)

= 198 cm²

∴ Hence, surface area will be reduced and the difference = 270 cm² – 198 cm² = 72 cm²