What is a vertex in math? When two lines or rays intersect and cross at one endpoint or vertex, a vertex angle is created. This angle, which is expressed in degrees, is sometimes confused with the face angle. Two intersecting lines at the corner of a 2D object, such as a polygon, create a vertex angle. In 3D forms, however, multiple angles are conceivable since there are more than two lines.
Let’s learn more about the vertex angle, the definition of the vertex, and the vertex angle in its many forms so that we may have a better knowledge of the concept.
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What is a Vertex in Math?
In mathematics, particularly graph theory, the fundamental component of a graph is referred to as a vertex (plural vertices), however, it is also referred to as a node. A directed graph is made up of a set of vertices and a set of arcs, whereas an undirected graph is made up of a set of vertices and a set of edges (unordered pairings of vertices). An arc connects two vertices in a directed graph (ordered pairs of vertices). In a diagram of a graph, a vertex is often represented by a circle with a label, and an edge is typically represented by a line or arrow that connects two of the diagram’s vertex points.
From the standpoint of graph theory, vertices are seen as featureless and indivisible objects, even though they could have an extra structure based on the application that spawned the graph. For instance, a semantic network is a graph in which the vertices represent different ideas or groups of things.
The edge is said to be incident to the vertices and to have the two vertices creating it as its ends. If there is an edge in the graph, a vertex w is considered to be close to a vertex v. (v,w). The vertices around a vertex (v) together constitute the neighborhood of that vertex, which is an induced subgraph of the graph.
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Features of a Vertex
Linear subdivisions and rays
A portion of a line is referred to as a line segment. A ray is a portion of a line that may be extended into the infinite future. An angle is created whenever two line segments or rays come together in one location. When two lines intersect to produce an angle, this is referred to as the formation of a vertex. Therefore, we may say that a vertex is formed when two line segments or rays meet to make a connection.
2D figures
A form or shape that is capable of being represented in two dimensions or on paper is referred to as a 2D shape or a two-dimensional figure. Circles, squares, rectangles, and triangles are all examples of two-dimensional forms. The point at which two of the figure’s sides cross is known as the vertex of a two-dimensional figure. When the two sides of the shape or figure come together to create an angle, this results in the formation of a vertex.
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3D figures
A figure or substance that is depicted in 3D space is referred to as having a three-dimensional, or 3D, representation. A 3-dimensional shape, often known as a solid form, has all three dimensions – namely, length, width, and height. The point at which two of a three-dimensional figure’s sides cross is known as the vertex of the figure.
In a three-dimensional shape, there may be several edges and sides that converge at a single point. A vertex is created at every site where two lines connect in this way. Cubes, cuboids, pyramids, spheres, and cylinders are all examples of three-dimensional forms.
Properties of a Vertex
- A figure or object does not have a vertex if it does not have any sides or edges to define its boundaries. Spheres, cylinders, and circles, to name a few, do not have any vertices on their surfaces.
- When two lines come together to produce a vertex at a point, they do so simultaneously by creating an internal angle for the figure.
Types of Vertexes
The degree of a vertex is denoted by the symbol v in a graph, which is determined by the number of edges that are incident to the vertex.
- Isolated vertex: One may say that a vertex is isolated if it has a degree of zero, which means that it is not the terminal of any edge.
- Leaf vertex (also pendant vertex): A vertex that has a degree of one is often referred to as a leaf vertex or a pendant vertex. A vertex with an indegree of zero is referred to as a source vertex, while a vertex with an outdegree of zero is referred to as a sink vertex. In a directed graph, it is possible to differentiate between the outdegree (the number of outgoing edges), indicated by the symbol +(v), and the indegree (the number of entering edges), denoted by the symbol v.
- Simplicial vertex: A vertex is said to have simplicial characteristics if its neighbors are close to one another and form a clique. The term “universal vertex” refers to a node in the network that has connections to each and every other node in the network.

- Cut vertex: A vertex that, if removed, would cut the remaining graph into smaller pieces is referred to as a cut vertex. On the other hand, a vertex separator is referred to as a group of vertices that, if removed, would cut the remaining graph into smaller pieces.
- K-vertex-connected graph: If a network loses fewer than k vertices, the remaining vertices are constantly connected, turning the graph into a k-vertex-connected structure. A vertex cover is a collection of vertices that has at least one endpoint for every edge in the graph, while an independent set is a collection of vertices that do not include any vertices that are contiguous with one another. Vertex space is a vector space that contains a collection of basis vectors that correspond to the vertices of the graph. Vertex space is a property of graphs.
- Vertex-transitive: It is said of a graph that it is vertex-transitive if it contains symmetries that may map every vertex to any other vertex. When talking about graph enumeration and graph isomorphism, it is important to make a distinction between labeled vertices and unlabeled vertices.
- Labeled vertex: Two graphs are only considered to be isomorphic with one another if the connection between the vertices of both graphs couples together vertices that have the same labels. Labeled vertices are vertices that are associated with extra information that distinguishes them from other labeled vertices. A vertex is considered to be labeled when it has this additional information connected with it.
- Unlabeled vertex: An unlabeled vertex is a vertex that can be substituted for any other vertex in the network based only on the adjacencies that it has with other vertices and does not need the usage of any additional information.
Although the vertices of a graph formed by the skeleton of a polyhedron are the same as the vertices of the graph formed by the polyhedron itself, the vertices of a polyhedron have an additional structure (their geometric location) that is not assumed to be present in graph theory.
Vertices in graphs are similar to the vertices of polyhedra, although they are not the same thing at all. A vertex’s immediate surroundings in a graph are analogous to the vertex figure that surrounds that vertex in a polyhedron.
Vertex Angle in Solid Shapes
Not only do plane forms include vertices, but so do solid shapes. Vertices are generated anywhere two edges of a shape meet. The vertex is not formed by the lines intersecting one another; rather, the vertex is formed by the corners or edges of the solid shape that are at right angles to one another.
Consider the illustration of a cube, which has four corners and four edges; each of them is a vertex, giving the cube a total of eight vertices. When referring to shapes like triangles and pyramids, vertices are often also referred to as the top or apex of the form. This top corner, known as the vertex or apex, is located directly above the base of the base.
We may utilize Euler’s formula, which is shown below, to determine the locations of the vertices in a solid shape.
F + V – E = 2
Where,
- F is the total number of people’s faces.
- V denotes the vertices.
- E represents the total number of edges.
Vertex Angle of a Parabola
A parabola is a shape that is produced when a quadratic equation is graphed. The precise point at which a parabola makes its turn is known as the vertex of the curve. This point is also referred to as the minimum point if the curve has the form of a “U.” The vertex of the parabola, at the point when it opens downward, is referred to as the maximum point (assuming the parabola is of the form “). The axis of symmetry passes via the vertex of the parabola.
Final Words
What is a vertex in math? The answer has been detailedly mentioned above. Hope that this vertex information can be beneficial for you during the process of solving math problems. If you are planning to teach your kids about this essential topic, you can make your own collections of Vertex worksheets using our worksheet generator.