Cubes

🏆Practice cubes

A cube is a type of cuboid in which all three dimensions (length, width and height) are identical. All cubes are made up of of six identical squares.

To find the volume of a cube we must go through the same steps as to find the volume of an cuboid, that is:

Length (L) × Depth (W) × Height (H).

Since the length, width and height are all equal, we only need to know one of them to calculate the volume.

C -Calculation volume of a cube

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Test yourself on cubes!

A cube has a total of 14 edges.

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Example exercise: volume and surface area of a cube

We have a cube whose length is 2 2 cm and we are asked to find its volume and surface area.


Finding the volume of a cube

The volume of a cube is equal to length × width × height.

Since the length, width and height of a cube are all equal, in our case the width and height of our given cube will also be 2 2 cm. Therefore,

8=2×2×2 8=2\times2\times2


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Finding the surface area of a cube

To find the total surface area of a cube, we will first find the surface area of one of its faces and then multiply the result by 6 (remember that cubes are composed of six identical square faces).

The area of each square is
4=2×2 4=2\times2

Therefore, the surface area of the cube will be:

4×6=24cm 4×6=24\operatorname{cm}


If you found this article helpful, you may also be interested in the following:

How to calculate the area of an orthohedron - rectangular prism or cube.

How to Calculate the Volume of a Rectangular Prism (Orthohedron)

Orthohedron - rectangular prism

For a wide range of mathematics articles visit Tutorela's website.


Example exercises

Example exercise 1

What is the volume of the cube

Given that:

The length of each side of the given cube is equal to 3 3 cm.

Question:

What is the volume of the cube?

Solution:

The volume of a cube (and the volume of a cuboid) is equal to:

Length × Width × Height

Therefore the volume of the cube: =33=27 =3^3=27

Answer:

27 cm3 27~cm³


Do you know what the answer is?

Example exercise 2

Given that:

Exercise 2 What is the surface area of the cube?

Given a cube in which each face has a surface area of 6 6 cm.

Assignment:

What is the total surface area of the cube?

Solution:

The total surface area of the cube is the combined area of all of its faces, ie:

Face area

6×6=36 6\times6=36

Answer:

36 cm2 36~cm²


Example exercise 3

Exercise 3 - What is the length of the diagonal of the face?

Given that:

In the given cube, the length of each edge is equal to 33 cm.

Question:

What is the length of the diagonal of the face?

Solution:

To solve this question we will use the Pythagorean Theorem to find the length of the diagonal of the face:

A2+B2=C2 A^2+B^2=C^2

Or, in our case:

Edge2+Edge2=Diagonal2 Edge^2+Edge^2=Diagonal^2

=32+32 =3^2+3^2

=18 =18

18=3×2=diagonal \sqrt{18}=3\times\sqrt{2}=diagonal

Answer:

323\sqrt{2}


Check your understanding

Example exercise 4

Exercise 4 - Given a cube whose edge length is equal to 5 cm

Given a cube whose edge length is equal to 5 5 cm.

Task:

Find the volume of the cube.

Solution:

The volume of the cube is equal to the length of the face of the cube to the power of 3 3

We can write it like this:

53=125 5^3=125

Answer:

125 cm3 125~cm³


Example exercise 5

Exercise 5 Given a cube whose volume equals 112 cc

Given a cube whose volume is equal to 112 112 cm³

Question:

How many whole cubes with a volume of 10 10 cm³ can fit inside the given cube?

Solution:

We divide the volume of the large cube into 10 10 to find out how many cubes of 10 10 cm³ fit into the given cube:

11210=1115 \frac{112}{10}=11\frac{1}{5}

Since we are only asked about whole cubes, it is possible to enter 11 11 cubes into the cube whose volume is 112 112 cm³.

Answer:

11 11 cubes.


Do you think you will be able to solve it?

Review questions

What is a cube?

A cube is a cuboid with six square, equal faces (all the sides are equal).


How do we find the surface area of a cube?

To find the total surface area of a cube, all we need is the value of one of its sides (since all sides are equal).

Then, we find the surface area of one face by multiplying the side to the power of three.

Lastly, we multiply the surface area of one face by six (since cubes have six equal sides).

Example exercise

Task. Find the total surface area of the following given cube, which has a side length of 7cm 7\operatorname{cm}

How to calculate the surface area of a cube

Solution:

Let's start by finding the area of just one face:

Area=7cm×7cm=49cm2 Area=7\operatorname{cm}\times7\operatorname{cm}=49\operatorname{cm^2}

Now, let's multiply the area of one face by six to find the total surface area:

49cm2×6=294cm2 49\operatorname{cm^2}\times6=294\operatorname{cm^2}

Answer:

=294cm2 =294 \operatorname{cm^2}


Test your knowledge

What is the formula used to find the volume of a cube?

The find the volume of a cube, we multiply its three sides.

Remember: since each face is square, all its sides have the same length.

= = ,× \times

This formula can also be expressed as:

V=L3 V=L^3

since all the sides are equal.


Finding the volume of a cube: additional practice

Example 1

Task. Find the volume of a cube with a side length of4cm 4\operatorname{cm}

how to calculate the volume of the following cubes

Solution:

Using our formula, we get:

V=L3 V=L^3

V=(4cm)3=64cm3 V=\left(4\operatorname{cm}\right)^3=64\operatorname{cm^3}

Answer

V=64cm3 V=64\operatorname{cm^3}


Example 2

Task. Find the volume of a cube with a side length of 8cm 8\operatorname{cm}

Calculate the volume of the cube of edge

Solution:

Again, we will use our formula to find the volume:

V=L3 V=L^3

V=(8cm)3=512cm3 V=\left(8\operatorname{cm}\right)^3=512\operatorname{cm^3}

Answer

V=512cm3 V=512\operatorname{cm^3}


Do you know what the answer is?

Examples with solutions for Cubes

Exercise #1

A cube has a base area of 9 cm².

Is it possible to calculate the volume of the cube? If so, what is it?

Video Solution

Step-by-Step Solution

To determine if we can calculate the volume of the cube, let's start by analyzing the given information:

  1. The base area of the cube is given as 9cm29 \, \text{cm}^2. In a cube, each face is a square, so this area corresponds to the area of one face.
  2. To find the side length ss of the square face, use the formula for the area of a square: A=s2A = s^2.
  3. Set up the equation based on the given area: s2=9s^2 = 9.
  4. Solve for ss by taking the square root of both sides: s=9=3cms = \sqrt{9} = 3 \, \text{cm}.
  5. Now that we have the side length ss, calculate the volume VV of the cube using the formula for the volume of a cube: V=s3V = s^3.
  6. Substitute s=3cms = 3 \, \text{cm} into the volume formula: V=33=27cm3V = 3^3 = 27 \, \text{cm}^3.

Therefore, the volume of the cube is 27cm327 \, \text{cm}^3.

Among the given choices, the correct answer is:

  • Choice 3: 27 27

Answer

27 27

Exercise #2

All faces of the cube must be?

Video Solution

Step-by-Step Solution

To determine what all the faces of a cube must be, we start by recalling the definition of a cube. A cube is a special type of cuboid where all edges are equal in length and all angles between the faces are right angles.

Since all edges are equal, each face of the cube is a square. A square is defined as a quadrilateral with equal sides and four right angles. This characteristic matches every face of a cube.

We recognize that the only shape for each face that satisfies the criteria of equal edge lengths and right angles is a square.

Therefore, all faces of the cube must be Squares.

Answer

Squares

Exercise #3

Which of the following figures represents an unfolded cube?

Video Solution

Step-by-Step Solution

To determine which figure represents an unfolded cube, we need to ensure the following:

  • The figure must consist of exactly 6 squares.

  • The squares must be connected along their edges to allow the figure to fold into a cube without overlapping.

Let's examine each of the choices:

  • Choice 1: This figure consists of 6 squares arranged in a "T" shape. By folding the squares, we can form a cube, which is a valid unfolded cube shape.

  • Choice 2: This figure consists of only 5 squares, which is insufficient to form a cube.

  • Choice 3: This figure also has 6 squares, but the arrangement will not form a cube since the squares aren't in a connected format that allows a full enclosure.

  • Choice 4: This figure consists of 7 squares, having an extra square, which invalidates it as a cube net.

Therefore, after examining all options, we conclude that Choice 1 is the correct one, as it can be folded into a cube.

Answer

Exercise #4

Shown below is a cube with a length of 4 cm.

What is the sum of the lengths of the cube's edges?

444

Video Solution

Step-by-Step Solution

To find the sum of the lengths of all the edges of a cube, we can follow these steps:

  • Step 1: Recognize that a cube has 12 edges, and each edge is the same length.
  • Step 2: Given the side length of the cube is 4 cm, use the formula for the total edge length.

The formula for the total length of the edges of a cube is:

Total length=number of edges×length of one edge \text{Total length} = \text{number of edges} \times \text{length of one edge}

Substituting the known values, we have:

Total length=12×4cm \text{Total length} = 12 \times 4 \, \text{cm}

Calculating this gives:

Total length=48cm \text{Total length} = 48 \, \text{cm}

Therefore, the sum of the lengths of the cube's edges is 48cm 48 \, \text{cm} .

Answer

48 48

Exercise #5

A cube has a total of 14 edges.

Video Solution

Step-by-Step Solution

To solve this problem, we'll analyze the basic properties of a cube as follows:

  • Step 1: Recall that a cube has 6 faces, 12 edges, and 8 vertices.
  • Step 2: Crucially, each face of a cube is a square, and a cube has exactly three edges meeting at each vertex.
  • Step 3: Count the edges: A cube's geometry dictates that it has 12 edges since each cube has 4 edges per face, shared equally among its 6 square faces.

Now, let's perform a check by thinking through the geometry:

A cube consists of 66 faces and each face shares its edges with adjacent faces. The twelve unique edges appear as 6×4÷26 \times 4 \div 2 edges (since each edge is counted twice, once on each adjoining face).

Thus, it is evident that a cube has exactly 12 edges, not 14.

Therefore, the statement that a cube has 14 edges is False.

Answer

False.

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