A 4 cm cube is cut into 1 cm cubes. Calculate the total surface area of all the small cubes.
Answer
685.5k+ views
Hint: Volume of a cube is \[{{a}^{3}}\] where \[a\] is the edge of the cube. So, we will calculate the volume of the cube for 4 cm and 1 cm and then use these two volumes to get the number of cubes of 1 cm edge.
Complete step-by-step answer:
Before proceeding with the question we should know about cube. A cube is a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex. It has 6 faces, 12 edges, and 8 vertices.
Volume of a cube \[=V={{a}^{3}}........(1)\]
So now finding the volume of a 4 cm cube by putting \[a=4\,cm\] in equation (1) we get,
\[\Rightarrow V={{4}^{3}}=64\,c{{m}^{3}}..........(2)\]
As it is mentioned in the question that a 4 cm cube is cut into 1 cm cubes, so now finding the volume of a 1 cm cube by putting \[a=1\,cm\] in equation (1) we get,
\[\Rightarrow V={{1}^{3}}=1\,c{{m}^{3}}.........(3)\]
If we divide the volume of a 4 cm cube by the volume of a 1 cm cube we get the total number of 1 cm cubes. So for doing this, we divide equation (2) by equation (3) and we get,
Total number of 1 cm cubes \[=\dfrac{64}{1}=64.........(4)\]
Surface area of a cube \[=6\times {{a}^{2}}.......(5)\]
So now finding the surface area of a 1 cm cube by putting \[a=1\]cm in equation (5) we get,
Surface area of a 1 cm cube \[=6\times {{1}^{2}}=6\,c{{m}^{2}}.........(6)\]
Now by multiplying equation (4) with equation (6) we get,
Total surface area of all 64 small cubes \[=64\times 6\,c{{m}^{2}}=384\,c{{m}^{2}}\]
Hence the answer is \[384\,c{{m}^{2}}\].
Note: Remembering the formula of volume and surface area of a cube is the key here. We can make a mistake in a hurry in calculating the total number of 1 cm cubes. And as we are calculating area and unit of area is \[c{{m}^{2}}\] so we should not forget to write the unit otherwise marks will be deducted.
Complete step-by-step answer:
Before proceeding with the question we should know about cube. A cube is a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex. It has 6 faces, 12 edges, and 8 vertices.
Volume of a cube \[=V={{a}^{3}}........(1)\]
So now finding the volume of a 4 cm cube by putting \[a=4\,cm\] in equation (1) we get,
\[\Rightarrow V={{4}^{3}}=64\,c{{m}^{3}}..........(2)\]
As it is mentioned in the question that a 4 cm cube is cut into 1 cm cubes, so now finding the volume of a 1 cm cube by putting \[a=1\,cm\] in equation (1) we get,
\[\Rightarrow V={{1}^{3}}=1\,c{{m}^{3}}.........(3)\]
If we divide the volume of a 4 cm cube by the volume of a 1 cm cube we get the total number of 1 cm cubes. So for doing this, we divide equation (2) by equation (3) and we get,
Total number of 1 cm cubes \[=\dfrac{64}{1}=64.........(4)\]
Surface area of a cube \[=6\times {{a}^{2}}.......(5)\]
So now finding the surface area of a 1 cm cube by putting \[a=1\]cm in equation (5) we get,
Surface area of a 1 cm cube \[=6\times {{1}^{2}}=6\,c{{m}^{2}}.........(6)\]
Now by multiplying equation (4) with equation (6) we get,
Total surface area of all 64 small cubes \[=64\times 6\,c{{m}^{2}}=384\,c{{m}^{2}}\]
Hence the answer is \[384\,c{{m}^{2}}\].
Note: Remembering the formula of volume and surface area of a cube is the key here. We can make a mistake in a hurry in calculating the total number of 1 cm cubes. And as we are calculating area and unit of area is \[c{{m}^{2}}\] so we should not forget to write the unit otherwise marks will be deducted.
Recently Updated Pages
Write any three differences between metals and nonmetals class 10 social science CBSE

Amit standing on a horizontal plane finds a bird flying class 10 maths CBSE

Two circles of radii 5 cm and 3 cm intersect at two class 10 maths CBSE

Solve the following i John and Jivanti together have class 10 maths CBSE

What is the relation between orthocenter circumcentre class 10 maths CBSE

Two plane mirrors are inclined at 70circ A ray incident class 10 physics CBSE

Trending doubts
Explain the Treaty of Vienna of 1815 class 10 social science CBSE

1 GB equals how many MB?

10 examples of evaporation in daily life with explanations

What is the full form of POSCO class 10 social science CBSE

Which is the hottest planet in the Solar system A Earth class 10 social science CBSE

Name any four life processes in living things class 10 biology CBSE

