Question

Hema was making a model, in which she placed 4 cubes each of edge 20cm one above the other. Find the surface area of the resulting cuboid.​

Answer 1

Answer:

Step-by-step explanation:

The formula to find the surface of a cuboid is

T.S.A of cuboid=2 (lb + bh +hl)

Given,

side of cube=20cm

In the cuboid formed,

The length = 20+20+20+20

                          = 80cm

Also,  its height = breadth = 20cm

T.S.A of cuboid = 2 (lb + bh +hl)

             =2[(80*20) + (20*20) + (80*20)]

             =2(1600 + 400 + 1600)

             =2*3600

             =7200 cm²

Therefore, the surface area of the resulting cuboid = 7200 cm²

Answer 2

Answer:

Give, edge of cube a=20cm.

Volume of cube = a3=203=8000cm3.

If cubes of edge [b=4cm] ismade from this cube, then

its volume =43=64cm3.

Let x cubes can be made.

Therefore,

Volume of large cube = x× Volume of small cube ....[a3=xb3]

⇒8000=x×64

⇒x=648000

⇒x=125.