Examples with solutions for Cubes: Express using

Exercise #1

Express the volume of the cube below in terms of a.

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Video Solution

Step-by-Step Solution

In this problem, we are tasked with expressing the volume of a cube given its side length a a .

To find the volume of the cube, we use the standard volume formula for a cube, which is given by:

V=side length3 V = \text{side length}^3

Since the side length of this cube is a a , we substitute a a into the formula:

V=a3 V = a^3

Thus, the volume of the cube in terms of a a is a3 a^3 .

We compare this with the provided answer choices:

  • Choice 1: a3 a^3
  • Choice 2: 6a3 6a^3
  • Choice 3: 6a2 6a^2
  • Choice 4: a2 a^2

Our computed volume a3 a^3 matches Choice 1.

Therefore, the correct choice is: a3 a^3 .

Answer

a3 a^3

Exercise #2

What is the surface area of the cube below in terms of X?

XXX

Video Solution

Step-by-Step Solution

To solve this problem, we'll determine the surface area using the formula for a cube:

  • Step 1: Identify the given information — Each side of the cube is XX.
  • Step 2: Recall the surface area formula — For a cube, it is 6×(side length)26 \times (\text{side length})^2.
  • Step 3: Substitute the side length XX into the formula.

Now, let's proceed with the solution:
Step 1: The cube has each side =X= X.
Step 2: The surface area formula for a cube is given by 6×(side length)26 \times (\text{side length})^2.
Step 3: Substituting XX for the side length, we find the surface area is 6×X26 \times X^2.

Therefore, the surface area of the cube in terms of XX is 6X2\mathbf{6X^2}.

Answer

6x2 6x^2

Exercise #3

Express the surface area of the cube in terms of a.

aaa

Video Solution

Step-by-Step Solution

To solve this problem, we'll recall the following relevant formula:

  • The surface area of a cube is given by the formula: Surface Area=6a2 \text{Surface Area} = 6a^2 .

Let's break down the solution in steps:

Step 1: Identify the characteristic of the cube.
A cube is a three-dimensional shape with six identical square faces.

Step 2: Determine the area of one face.
Each face of the cube is a square with side length a a , so the area of one face is a2 a^2 .

Step 3: Calculate the total surface area.
Since a cube has six identical faces, the total surface area is six times the area of one face:

Surface Area=6×a2=6a2 \text{Surface Area} = 6 \times a^2 = 6a^2

Therefore, the surface area of the cube in terms of a a is 6a2 6a^2 .

Answer

6a2 6a^2