Answer :

Let's break this problem down into a step-by-step solution.

### Part (i) and (ii)

While parts (i) and (ii) mention specific dimensions, these don't seem directly related to the construction of the square with a side length of [tex]\(\sqrt{8}\)[/tex]. So, we'll focus on the construction of the square as specified in part (5).

### Part (5): Constructing the Square with Side [tex]\(\sqrt{8}\)[/tex]

We need to construct a square with a side length of [tex]\(\sqrt{8}\)[/tex] units without calculating the exact value of [tex]\(\sqrt{8}\)[/tex].

Here’s how we can visualize and describe the construction:

1. Point 1: Start at the origin point [tex]\((0, 0)\)[/tex]. This will be one vertex of the square.

2. Point 2: Move horizontally to the right from [tex]\((0, 0)\)[/tex] to a point [tex]\((\sqrt{8}, 0)\)[/tex]. This forms one side of the square along the x-axis.

3. Point 3: From [tex]\((\sqrt{8}, 0)\)[/tex], move vertically upward by the same distance ([tex]\(\sqrt{8}\)[/tex]) to reach a point [tex]\((\sqrt{8}, \sqrt{8})\)[/tex]. This forms the right side of the square parallel to the y-axis.

4. Point 4: From [tex]\((0, 0)\)[/tex], move vertically upward by [tex]\(\sqrt{8}\)[/tex] to the point [tex]\((0, \sqrt{8})\)[/tex]. This completes the left side of the square.

Once we have these points, using these logical coordinates, the square is constructed and we have:

- Point 1: [tex]\((0, 0)\)[/tex]
- Point 2: [tex]\((\sqrt{8}, 0)\)[/tex]
- Point 3: [tex]\((\sqrt{8}, \sqrt{8})\)[/tex]
- Point 4: [tex]\((0, \sqrt{8})\)[/tex]

Therefore, we have successfully constructed a square whose side length is [tex]\(\sqrt{8}\)[/tex] units, and we can specify its vertices explicitly:

- [tex]\((0, 0)\)[/tex]
- [tex]\((\sqrt{8}, 0)\)[/tex]
- [tex]\((\sqrt{8}, \sqrt{8})\)[/tex]
- [tex]\((0, \sqrt{8})\)[/tex]

Numerically, these points are:

- Point 1: [tex]\((0, 0)\)[/tex]
- Point 2: [tex]\((2.8284271247461903, 0)\)[/tex]
- Point 3: [tex]\((2.8284271247461903, 2.8284271247461903)\)[/tex]
- Point 4: [tex]\((0, 2.8284271247461903)\)[/tex]

Hence, the square with side [tex]\(\sqrt{8}\)[/tex] units has been constructed accurately with the specified coordinates.

Finally, the results are:

- Part (i): 6.4 cm
- Part (ii): 10.8 cm
- Vertices of the square:
- [tex]\((0, 0)\)[/tex]
- [tex]\((2.8284271247461903, 0)\)[/tex]
- [tex]\((2.8284271247461903, 2.8284271247461903)\)[/tex]
- [tex]\((0, 2.8284271247461903)\)[/tex]