Question

3: 2 cubes each of volume 64 cm^3 are joined end to end. Find the surface area of the resulting cuboid.​

Answer 1

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Given,

The Volume (V) of each cube is = 64 cm^3

This implies that a^3 = 64 cm^3

∴ The side of the cube i.e. a = 4 cm

Also,

the breadth and length of the resulting cuboid will be 4 cm each while its height will be 8 cm.

So, the surface area of the cuboid

(TSA) = 2(lb + bh + lh)

Now, by putting the values we get,

= 2(8×4 + 4×4 + 4×8) cm^2

= (2 × 80) cm^2

Hence, TSA of the cuboid = 160 cm^2.

Answer 2

Answer:

Given, volume of each cube is 64 cm³

⇒s³=64

⇒s=∛64

⇒s=4 cm.

When two cubes are joined , 

the length of the resulting cuboid(l) = side + side = 4+4 = 8 cm

its breadth(b) = side = 4cm

And its height(h) = side = 4cm

Total surface area of a cuboid = 2(lb+bh+hl)

⇒TSA=2[(8)(4)+(4)(4)+(4)(8)]

⇒TSA=2(32+16+32)

⇒TSA = 2(80)

⇒TSA = 160 cm²

∴ The surface area of the resulting cuboid is 160 cm².

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