Request a call back

Three equal cubes are placed together in a row to form a cuboid. Find the ratio of the total surface area of the new cuboid to that of the surface area of the three cubes.
Asked by Cl_narayan | 17 Jul, 2019, 03:51: PM

Let the side of the cube be a units.

Total Surface area of the new cuboid) = 6a2

Three equal cubes are placed together in a row to form a cuboid.

Sum of the total surface area of the three cubes= 3(6a2)= 18a2

Total Surface area of a Cuboid = 2(lb + bh + hl)   ... (1)

Three equal cubes are placed together in a row to form a cuboid.

→ The dimensions of the new Cuboid are l = a + a + a = 3a, b = a and h = a.

Substituting the values of l, b and h in the equation (1), we get

Total Surface area of a Cuboid = 2(3a × a + a × a + a × 3a)
= 2(3a + a2 + 3a2)
= 14a2
The ratio of the total surface area of the new cuboid to that of the surface area of the three cubes
= 14a2 ÷ 18a = 7 ÷ 9 = 7: 9
Answered by Yasmeen Khan | 17 Jul, 2019, 04:29: PM

## Concept Videos

ICSE 8 - Maths
Asked by sy7730348 | 17 Feb, 2022, 02:27: PM
ICSE 8 - Maths
Asked by hchandrashekar751 | 01 Feb, 2022, 01:40: PM
ICSE 8 - Maths
Asked by Cl_narayan | 14 Feb, 2020, 12:41: PM
ICSE 8 - Maths
Asked by Cl_narayan | 31 Aug, 2019, 04:41: PM