Question

two cubes each of volume 125cm cube are joined end to end .find the surface area of resulting cuboid

Answer 1

To find out the answer, First, let us find the side of the cube, 
As you said it has a volume of 125 cm³, we can find it's side,

Volume of a general cube is it's side³,
Assuming side as a, 
Now,
a³ = 125 cm³,
=> a = 5 cm,

Now, We got the side of the cube, If two cubes are joined each other then, We can say that only length is changed, but breadth and height remain constant,

I am sorry that I can't provide you the diagram, But please do Imagine it,

Now, In the resulting cuboid, the length is 5+5 cm, and breadth = 5cm, and height is 5cm,

=> Length = 10 cm,
=> Breadth = 5 cm,
=> Height = 5 cm,

In general surface area means, Total Surface area,
and also, the Total Surface area of a cuboid of dimensions l*b*h is 2(lb+bh+lh),

Now, Substituting all the values of cuboid to find the Surface area,
=> Surface area of resulting cuboid is 2(10*5 + 5*5 + 10*5),
=> Surface Area = 2(50+25+50),
=> Surface area = 2(125),
=> Surface area = 250 cm²,

Therefore the answer to your question is 250 cm²,

Hope you understand, Have a Great day!
Thanking you, Bunti 360!

Answer 2

Let the side of a cube =a

Volume of the cube = a

3

a

3

=125

a

3

=5

3

a=5 cm

If two cubes are joined end to end it becomes cuboid.

Dimensions of cuboid are

Lengh =l=10 cm

Breadth =b=5 cm

height =h=5 cm

Lateral surface Area = 2(l+b)h=2(10+5)5

=2×15×5=15059cm

Total surface Area = 2(lb+bh+lh)

=2(10×5+5×5+5×10)

=2(50+25+50)

=2(125)

=250sq.cm

Volume = lbh=10×5×5=250 cubic cm