Answer :
Certainly! Let's address each part of the question step by step.
### 1. Finding the Number of Vertices using [tex]\( V + F - 2 = E \)[/tex]
#### a. Octahedron (8 faces):
Given:
- Faces ([tex]\( F \)[/tex]) = 8
We start with the equation [tex]\( V + F - 2 = E \)[/tex].
To find the number of vertices ([tex]\( V \)[/tex]):
1. Rearrange the equation to find [tex]\( E \)[/tex]:
[tex]\[ V + F - 2 = E \Rightarrow E = 2F - 4 \][/tex]
2. Substituting [tex]\( F \)[/tex] with 8:
[tex]\[ E = 2(8) - 4 = 16 - 4 = 12 \][/tex]
3. Now, substitute [tex]\( E \)[/tex] back into the original equation to solve for [tex]\( V \)[/tex]:
[tex]\[ V + 8 - 2 = 12 \][/tex]
[tex]\[ V + 6 = 12 \][/tex]
[tex]\[ V = 12 - 6 \][/tex]
[tex]\[ V = 6 \][/tex]
Therefore, an octahedron has 6 vertices.
#### b. Icosahedron (30 edges):
Given:
- Edges ([tex]\( E \)[/tex]) = 30
We start with the equation [tex]\( V + F - 2 = E \)[/tex].
To find the number of vertices ([tex]\( V \)[/tex]):
1. Let’s find a relationship for Faces ([tex]\( F \)[/tex]) first. From the equation:
[tex]\[ 2(V + F - 2) = 2E \Rightarrow 2V + 2F - 4 = 2E \Rightarrow 3F = 2E \][/tex]
[tex]\[ F = \frac{2E}{3} \][/tex]
2. Substituting [tex]\( E \)[/tex] with 30:
[tex]\[ F = \frac{2(30)}{3} = \frac{60}{3} = 20 \][/tex]
3. Now, substitute [tex]\( F \)[/tex] and [tex]\( E \)[/tex] back into the original equation to solve for [tex]\( V \)[/tex]:
[tex]\[ V + 20 - 2 = 30 \][/tex]
[tex]\[ V + 18 = 30 \][/tex]
[tex]\[ V = 30 - 18 \][/tex]
[tex]\[ V = 12 \][/tex]
Therefore, an icosahedron has 12 vertices.
### 2. Finding the Number of Faces for a Buckyball:
Given:
- Vertices ([tex]\( V \)[/tex]) = 60
We start with the equation [tex]\( V + F - 2 = E \)[/tex].
To find the number of faces ([tex]\( F \)[/tex]) if we know the number of edges ([tex]\( E \)[/tex]):
1. Rearrange the equation to express [tex]\( F \)[/tex]:
[tex]\[ F = E - V + 2 \][/tex]
Therefore, the equation to find the number of faces ([tex]\( F \)[/tex]) for a Buckyball given the number of edges ([tex]\( E \)[/tex]) is:
[tex]\[ F = E - 60 + 2 \][/tex]
Using this formula, if, for example, the Buckyball has 90 edges, we find the number of faces as follows:
[tex]\[ F = 90 - 60 + 2 = 32 \][/tex]
Therefore, a Buckyball with 90 edges has 32 faces.
The results are:
- An octahedron has 6 vertices.
- An icosahedron has 12 vertices.
- A Buckyball with 90 edges has 32 faces.
### 1. Finding the Number of Vertices using [tex]\( V + F - 2 = E \)[/tex]
#### a. Octahedron (8 faces):
Given:
- Faces ([tex]\( F \)[/tex]) = 8
We start with the equation [tex]\( V + F - 2 = E \)[/tex].
To find the number of vertices ([tex]\( V \)[/tex]):
1. Rearrange the equation to find [tex]\( E \)[/tex]:
[tex]\[ V + F - 2 = E \Rightarrow E = 2F - 4 \][/tex]
2. Substituting [tex]\( F \)[/tex] with 8:
[tex]\[ E = 2(8) - 4 = 16 - 4 = 12 \][/tex]
3. Now, substitute [tex]\( E \)[/tex] back into the original equation to solve for [tex]\( V \)[/tex]:
[tex]\[ V + 8 - 2 = 12 \][/tex]
[tex]\[ V + 6 = 12 \][/tex]
[tex]\[ V = 12 - 6 \][/tex]
[tex]\[ V = 6 \][/tex]
Therefore, an octahedron has 6 vertices.
#### b. Icosahedron (30 edges):
Given:
- Edges ([tex]\( E \)[/tex]) = 30
We start with the equation [tex]\( V + F - 2 = E \)[/tex].
To find the number of vertices ([tex]\( V \)[/tex]):
1. Let’s find a relationship for Faces ([tex]\( F \)[/tex]) first. From the equation:
[tex]\[ 2(V + F - 2) = 2E \Rightarrow 2V + 2F - 4 = 2E \Rightarrow 3F = 2E \][/tex]
[tex]\[ F = \frac{2E}{3} \][/tex]
2. Substituting [tex]\( E \)[/tex] with 30:
[tex]\[ F = \frac{2(30)}{3} = \frac{60}{3} = 20 \][/tex]
3. Now, substitute [tex]\( F \)[/tex] and [tex]\( E \)[/tex] back into the original equation to solve for [tex]\( V \)[/tex]:
[tex]\[ V + 20 - 2 = 30 \][/tex]
[tex]\[ V + 18 = 30 \][/tex]
[tex]\[ V = 30 - 18 \][/tex]
[tex]\[ V = 12 \][/tex]
Therefore, an icosahedron has 12 vertices.
### 2. Finding the Number of Faces for a Buckyball:
Given:
- Vertices ([tex]\( V \)[/tex]) = 60
We start with the equation [tex]\( V + F - 2 = E \)[/tex].
To find the number of faces ([tex]\( F \)[/tex]) if we know the number of edges ([tex]\( E \)[/tex]):
1. Rearrange the equation to express [tex]\( F \)[/tex]:
[tex]\[ F = E - V + 2 \][/tex]
Therefore, the equation to find the number of faces ([tex]\( F \)[/tex]) for a Buckyball given the number of edges ([tex]\( E \)[/tex]) is:
[tex]\[ F = E - 60 + 2 \][/tex]
Using this formula, if, for example, the Buckyball has 90 edges, we find the number of faces as follows:
[tex]\[ F = 90 - 60 + 2 = 32 \][/tex]
Therefore, a Buckyball with 90 edges has 32 faces.
The results are:
- An octahedron has 6 vertices.
- An icosahedron has 12 vertices.
- A Buckyball with 90 edges has 32 faces.