FACES
1
2
3
4
5
6
7
8
9
10
11
12
São as superfícies planas
que constituem o sólido
By counting the line segments,
a cube has 12 edges.
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
Correspondem às linhas
resultantes do encontro de duas
faces
ARESTAS
1
2
3
5
67
4
8
VÉRTICES
São os pontos de
encontro das arestas
PODEMOS CLASSIFICAR OS
POLIEDROS EM DOIS GRUPOS:
FORMULA RELAÇÃO DE EULER
V é o número de vértices
A é o número de arestas, e
F é o número de faces
Para os poliedros, existe outra forma de saber o número de arestas, vértices ou faces
dos sólidos, que é através da fórmula de Euler.
V + F = A + 2
Poliedro F V A F + V A + 2
Cubo 6 8 12 6 + 8 = 14 12 + 2 = 14
Pirâmide triangular 4 4 6 4 + 4 = 8 6 + 2 = 8
Prisma de base pentagonal 7 10 15 7 + 10 = 17 15 + 2 = 17
Octaedro regular 8 6 12 8 + 6 = 14 12 + 2 = 14
Podemos utilizar a relação de Euler para determinar ou confirmar valores
desconhecidos de V, F ou A, sempre que o poliedro for convexo.
Vertices =
Edges =
Faces =
?
What is the name of the solid?
?
?
TRY THIS!
How many vertices, edges and
faces does the solid have?
Vertices =
Edges =
Faces =
0
2
3
ANSWER
Notice that a cylinder has no corners,
which means it has 0 vertex.
The edges of the cylinder are the tops
and bottom lines.
The faces of a cylinder is composed of 1
curved face and the top and bottom faces.
Cylinder
polyhedron.
Since a cylinder
has 1 curved surface,
we can say that
it is not a
FORMULA RELAÇÃO DE EULER
V é o número de vértices
A é o número de arestas, e
F é o número de faces
Para os poliedros, existe outra forma de saber o número de arestas, vértices ou faces
dos sólidos, que é através da fórmula de Euler.
V + F - A = 2
EXAMPLE: EULER’S FORMULA WITH
POLYHEDRONS
A pyramid has 5 vertices
and 8 edges, how many
faces does it have?
EXAMPLE: EULER’S FORMULA WITH
POLYHEDRONS
Re-arrange the formula to solve for V.
Substitute the values.
Solve.
Step 1:
Step 2:
Step 3:
The pyramid has 5 vertices!
Edges = ?
TRY THIS!
How many edges does the solid have?
5 faces and 6 vertices
5 faces and 6 vertices
A triangular prism has 9 edges.
Re-arrange the formula to solve for E.
Substitute the values.
Solve.
Step 1:
Step 2:
Step 3:
ANSWER
RECAP:
Polyhedra
(polyhedron singular)
are solids that does not
have a curved surface.
Properties of Solids Polyhedra Euler’s Formula
Euler’s Formula can be used
to calcualte the vertices, faces
and edges of polyhedra.
where:
V is the number of vertices
E is the number of edges, and
F is the number of faces
Vertex
A corner where
lines meet.
Face
The surface
of the figure.
Edge
A line segment
between two vertices.
THINK
ABOUT IT!
Euler’s formula can be used to
calculate for the number of
vertices, edges and faces of
polyhedrons and it doesn’t work for
a non-polyhedron like a cylinder.
Why do you think so?
Share your answer in our next session.
Mathspace. "Faces, Edges, and Vertices in
Polyhedra | Secondary Math | UK Secondary
(7-11)" Accessed 22 February 2024,
https://mathspace.co/textbooks/syllabuses/
Syllabus-453/topics/Topic-8405/subtopics
/Subtopic-111199/?activeTab=theory
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