Request a call back

Join NOW to get access to exclusive study material for best results

ICSE Class 8 Answered

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
answered-by-expert Expert Answer
 
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
ANSWERED BY EXPERT ANSWERED BY EXPERT
ICSE 8 - Maths
Asked by l.kumar2412 | 30 Jul, 2019, 12:25: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
ICSE 8 - Maths
Asked by Surindersingh51001 | 14 Feb, 2019, 12:43: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
Get Latest Study Material for Academic year 24-25 Click here
×