Gumdrop Polyhedra Equipment: (1) Spice Drops of Many Colors. They
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Equivelar Octahedron of Genus 3 in 3-Space
Equivelar octahedron of genus 3 in 3-space Ruslan Mizhaev ([email protected]) Apr. 2020 ABSTRACT . Building up a toroidal polyhedron of genus 3, consisting of 8 nine-sided faces, is given. From the point of view of topology, a polyhedron can be considered as an embedding of a cubic graph with 24 vertices and 36 edges in a surface of genus 3. This polyhedron is a contender for the maximal genus among octahedrons in 3-space. 1. Introduction This solution can be attributed to the problem of determining the maximal genus of polyhedra with the number of faces - . As is known, at least 7 faces are required for a polyhedron of genus = 1 . For cases ≥ 8 , there are currently few examples. If all faces of the toroidal polyhedron are – gons and all vertices are q-valence ( ≥ 3), such polyhedral are called either locally regular or simply equivelar [1]. The characteristics of polyhedra are abbreviated as , ; [1]. 2. Polyhedron {9, 3; 3} V1. The paper considers building up a polyhedron 9, 3; 3 in 3-space. The faces of a polyhedron are non- convex flat 9-gons without self-intersections. The polyhedron is symmetric when rotated through 1804 around the axis (Fig. 3). One of the features of this polyhedron is that any face has two pairs with which it borders two edges. The polyhedron also has a ratio of angles and faces - = − 1. To describe polyhedra with similar characteristics ( = − 1) we use the Euler formula − + = = 2 − 2, where is the Euler characteristic. Since = 3, the equality 3 = 2 holds true. -
Archimedean Solids
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln MAT Exam Expository Papers Math in the Middle Institute Partnership 7-2008 Archimedean Solids Anna Anderson University of Nebraska-Lincoln Follow this and additional works at: https://digitalcommons.unl.edu/mathmidexppap Part of the Science and Mathematics Education Commons Anderson, Anna, "Archimedean Solids" (2008). MAT Exam Expository Papers. 4. https://digitalcommons.unl.edu/mathmidexppap/4 This Article is brought to you for free and open access by the Math in the Middle Institute Partnership at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in MAT Exam Expository Papers by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Archimedean Solids Anna Anderson In partial fulfillment of the requirements for the Master of Arts in Teaching with a Specialization in the Teaching of Middle Level Mathematics in the Department of Mathematics. Jim Lewis, Advisor July 2008 2 Archimedean Solids A polygon is a simple, closed, planar figure with sides formed by joining line segments, where each line segment intersects exactly two others. If all of the sides have the same length and all of the angles are congruent, the polygon is called regular. The sum of the angles of a regular polygon with n sides, where n is 3 or more, is 180° x (n – 2) degrees. If a regular polygon were connected with other regular polygons in three dimensional space, a polyhedron could be created. In geometry, a polyhedron is a three- dimensional solid which consists of a collection of polygons joined at their edges. The word polyhedron is derived from the Greek word poly (many) and the Indo-European term hedron (seat). -
Shape Skeletons Creating Polyhedra with Straws
Shape Skeletons Creating Polyhedra with Straws Topics: 3-Dimensional Shapes, Regular Solids, Geometry Materials List Drinking straws or stir straws, cut in Use simple materials to investigate regular or advanced 3-dimensional shapes. half Fun to create, these shapes make wonderful showpieces and learning tools! Paperclips to use with the drinking Assembly straws or chenille 1. Choose which shape to construct. Note: the 4-sided tetrahedron, 8-sided stems to use with octahedron, and 20-sided icosahedron have triangular faces and will form sturdier the stir straws skeletal shapes. The 6-sided cube with square faces and the 12-sided Scissors dodecahedron with pentagonal faces will be less sturdy. See the Taking it Appropriate tool for Further section. cutting the wire in the chenille stems, Platonic Solids if used This activity can be used to teach: Common Core Math Tetrahedron Cube Octahedron Dodecahedron Icosahedron Standards: Angles and volume Polyhedron Faces Shape of Face Edges Vertices and measurement Tetrahedron 4 Triangles 6 4 (Measurement & Cube 6 Squares 12 8 Data, Grade 4, 5, 6, & Octahedron 8 Triangles 12 6 7; Grade 5, 3, 4, & 5) Dodecahedron 12 Pentagons 30 20 2-Dimensional and 3- Dimensional Shapes Icosahedron 20 Triangles 30 12 (Geometry, Grades 2- 12) 2. Use the table and images above to construct the selected shape by creating one or Problem Solving and more face shapes and then add straws or join shapes at each of the vertices: Reasoning a. For drinking straws and paperclips: Bend the (Mathematical paperclips so that the 2 loops form a “V” or “L” Practices Grades 2- shape as needed, widen the narrower loop and insert 12) one loop into the end of one straw half, and the other loop into another straw half. -
VOLUME of POLYHEDRA USING a TETRAHEDRON BREAKUP We
VOLUME OF POLYHEDRA USING A TETRAHEDRON BREAKUP We have shown in an earlier note that any two dimensional polygon of N sides may be broken up into N-2 triangles T by drawing N-3 lines L connecting every second vertex. Thus the irregular pentagon shown has N=5,T=3, and L=2- With this information, one is at once led to the question-“ How can the volume of any polyhedron in 3D be determined using a set of smaller 3D volume elements”. These smaller 3D eelements are likely to be tetrahedra . This leads one to the conjecture that – A polyhedron with more four faces can have its volume represented by the sum of a certain number of sub-tetrahedra. The volume of any tetrahedron is given by the scalar triple product |V1xV2∙V3|/6, where the three Vs are vector representations of the three edges of the tetrahedron emanating from the same vertex. Here is a picture of one of these tetrahedra- Note that the base area of such a tetrahedron is given by |V1xV2]/2. When this area is multiplied by 1/3 of the height related to the third vector one finds the volume of any tetrahedron given by- x1 y1 z1 (V1xV2 ) V3 Abs Vol = x y z 6 6 2 2 2 x3 y3 z3 , where x,y, and z are the vector components. The next question which arises is how many tetrahedra are required to completely fill a polyhedron? We can arrive at an answer by looking at several different examples. Starting with one of the simplest examples consider the double-tetrahedron shown- It is clear that the entire volume can be generated by two equal volume tetrahedra whose vertexes are placed at [0,0,sqrt(2/3)] and [0,0,-sqrt(2/3)]. -
131 865- EDRS PRICE Technclogy,Liedhanical
..DOCUMENT RASH 131 865- JC 760 420 TITLE- Training Program for Teachers of Technical Mathematics in Two-Year Cutricnla. INSTITUTION Queensborough Community Coll., Bayside, N Y. SPONS AGENCY New York State Education Dept., Albany. D v.of Occupational Education Instruction. PUB DATE Jul 76 GRANT VEA-78-2-132 NOTE 180p. EDRS PRICE MP-$0.83 HC-S10.03 Plus Postage. DESCRIPTORS *College Mathematics; Community Colleges; Curriculum Development; Engineering Technology; *Junior Colleges Mathematics Curriculum; *Mathematics Instruction; *Physics Instruction; Practical ,Mathematics Technical Education; *Technical Mathematics Technology ABSTRACT -This handbook 1 is designed'to.aS ist teachers of techhical'mathematics in:developing practically-oriented-curricula -for their students. The upderlying.assumption is that, while technology students are nOt a breed apartr their: needs-and orientation are_to the concrete, rather than the abstract. It describes the:nature, scope,and dontett,of curricula.. in Electrical, TeChnClogy,liedhanical Technology4 Design DraftingTechnology, and: Technical Physics', ..with-particularreterence to:the mathematical skills which are_important for the students,both.incollege.andot -tle job. SaMple mathematical problemsr-derivationSeand.theories tei be stressed it..each of_these.durricula-are presented, as- ate additional materials from the physics an4 mathematics. areas. A frame ok-reference-is.provided through diScussiotS ofthe\careers,for.which-. technology students-are heing- trained'. There.iS alsO §ion deioted to -
Polyhedral Harmonics
value is uncertain; 4 Gr a y d o n has suggested values of £estrap + A0 for the first three excited 4,4 + 0,1 v. e. states indicate 11,1 v.e. för D0. The value 6,34 v.e. for Dextrap for SO leads on A rough correlation between Dextrap and bond correction by 0,37 + 0,66 for the'valence states of type is evident for the more stable states of the the two atoms to D0 ^ 5,31 v.e., in approximate agreement with the precisely known value 5,184 v.e. diatomic molecules. Thus the bonds A = A and The valence state for nitrogen, at 27/100 F2 A = A between elements of the first short period (with 2D at 9/25 F2 and 2P at 3/5 F2), is calculated tend to have dissociation energy to the atomic to lie about 1,67 v.e. above the normal state, 4S, valence state equal to about 6,6 v.e. Examples that for the iso-electronic oxygen ion 0+ is 2,34 are 0+ X, 6,51; N2 B, 6,68; N2 a, 6,56; C2 A, v.e., and that for phosphorus is 1,05 v.e. above 7,05; C2 b, 6,55 v.e. An increase, presumably due their normal states. Similarly the bivalent states to the stabilizing effect of the partial ionic cha- of carbon, : C •, the nitrogen ion, : N • and racter of the double bond, is observed when the atoms differ by 0,5 in electronegativity: NO X, Silicon,:Si •, are 0,44 v.e., 0,64 v.e., and 0,28 v.e., 7,69; CN A, 7,62 v.e. -
Just (Isomorphic) Friends: Symmetry Groups of the Platonic Solids
Just (Isomorphic) Friends: Symmetry Groups of the Platonic Solids Seth Winger Stanford University|MATH 109 9 March 2012 1 Introduction The Platonic solids have been objects of interest to mankind for millennia. Each shape—five in total|is made up of congruent regular polygonal faces: the tetrahedron (four triangular sides), the cube (six square sides), the octahedron (eight triangular sides), the dodecahedron (twelve pentagonal sides), and the icosahedron (twenty triangular sides). They are prevalent in everything from Plato's philosophy, where he equates them to the four classical elements and a fifth heavenly aether, to middle schooler's role playing games, where Platonic dice determine charisma levels and who has to get the next refill of Mountain Dew. Figure 1: The five Platonic solids (http://geomag.elementfx.com) In this paper, we will examine the symmetry groups of these five solids, starting with the relatively simple case of the tetrahedron and moving on to the more complex shapes. The rotational symmetry groups of the solids share many similarities with permutation groups, and these relationships will be shown to be an isomorphism that can then be exploited when discussing the Platonic solids. The end goal is the most complex case: describing the symmetries of the icosahedron in terms of A5, the group of all sixty even permutations in the permutation group of degree 5. 2 The Tetrahedron Imagine a tetrahedral die, where each vertex is labeled 1, 2, 3, or 4. Two or three rolls of the die will show that rotations can induce permutations of the vertices|a different number may land face up on every throw, for example|but how many such rotations and permutations exist? There are two main categories of rotation in a tetrahedron: r, those around an axis that runs from a vertex of the solid to the centroid of the opposing face; and q, those around an axis that runs from midpoint to midpoint of opposing edges (see Figure 2). -
900.00 Modelability
986.310 Strategic Use of Min-max Cosmic System Limits 986.311 The maximum limit set of identical facets into which any system can be divided consists of 120 similar spherical right triangles ACB whose three corners are 60 degrees at A, 90 degrees at C, and 36 degrees at B. Sixty of these right spherical triangles are positive (active), and 60 are negative (passive). (See Sec. 901.) 986.312 These 120 right spherical surface triangles are described by three different central angles of 37.37736814 degrees for arc AB, 31.71747441 degrees for arc BC, and 20.90515745 degrees for arc AC__which three central-angle arcs total exactly 90 degrees. These 120 spherical right triangles are self-patterned into producing 30 identical spherical diamond groups bounded by the same central angles and having corresponding flat-faceted diamond groups consisting of four of the 120 angularly identical (60 positive, 60 negative) triangles. Their three surface corners are 90 degrees at C, 31.71747441 degrees at B, and 58.2825256 degrees at A. (See Fig. 986.502.) 986.313 These diamonds, like all diamonds, are rhombic forms. The 30- symmetrical- diamond system is called the rhombic triacontahedron: its 30 mid- diamond faces (right- angle cross points) are approximately tangent to the unit- vector-radius sphere when the volume of the rhombic triacontahedron is exactly tetravolume-5. (See Fig. 986.314.) 986.314 I therefore asked Robert Grip and Chris Kitrick to prepare a graphic comparison of the various radii and their respective polyhedral profiles of all the symmetric polyhedra of tetravolume 5 (or close to 5) existing within the primitive cosmic hierarchy (Sec. -
What Is a Polyhedron?
3. POLYHEDRA, GRAPHS AND SURFACES 3.1. From Polyhedra to Graphs What is a Polyhedron? Now that we’ve covered lots of geometry in two dimensions, let’s make things just a little more difficult. We’re going to consider geometric objects in three dimensions which can be made from two-dimensional pieces. For example, you can take six squares all the same size and glue them together to produce the shape which we call a cube. More generally, if you take a bunch of polygons and glue them together so that no side gets left unglued, then the resulting object is usually called a polyhedron.1 The corners of the polygons are called vertices, the sides of the polygons are called edges and the polygons themselves are called faces. So, for example, the cube has 8 vertices, 12 edges and 6 faces. Different people seem to define polyhedra in very slightly different ways. For our purposes, we will need to add one little extra condition — that the volume bound by a polyhedron “has no holes”. For example, consider the shape obtained by drilling a square hole straight through the centre of a cube. Even though the surface of such a shape can be constructed by gluing together polygons, we don’t consider this shape to be a polyhedron, because of the hole. We say that a polyhedron is convex if, for each plane which lies along a face, the polyhedron lies on one side of that plane. So, for example, the cube is a convex polyhedron while the more complicated spec- imen of a polyhedron pictured on the right is certainly not convex. -
The Platonic Solids
The Platonic Solids William Wu [email protected] March 12 2004 The tetrahedron, the cube, the octahedron, the dodecahedron, and the icosahedron. From a ¯rst glance, one immediately notices that the Platonic Solids exhibit remarkable symmetry. They are the only convex polyhedra for which the same same regular polygon is used for each face, and the same number of faces meet at each vertex. Their symmetries are aesthetically pleasing, like those of stones cut by a jeweler. We can further enhance our appreciation of these solids by examining them under the lenses of group theory { the mathematical study of symmetry. This article will discuss the group symmetries of the Platonic solids using a variety of concepts, including rotations, reflections, permutations, matrix groups, duality, homomorphisms, and representations. 1 The Tetrahedron 1.1 Rotations We will begin by studying the symmetries of the tetrahedron. If we ¯rst restrict ourselves to rotational symmetries, we ask, \In what ways can the tetrahedron be rotated such that the result appears identical to what we started with?" The answer is best elucidated with the 1 Figure 1: The Tetrahedron: Identity Permutation aid of Figure 1. First consider the rotational axis OA, which runs from the topmost vertex through the center of the base. Note that we can repeatedly rotate the tetrahedron about 360 OA by 3 = 120 degrees to ¯nd two new symmetries. Since each face of the tetrahedron can be pierced with an axis in this fashion, we have found 4 £ 2 = 8 new symmetries. Figure 2: The Tetrahedron: Permutation (14)(23) Now consider rotational axis OB, which runs from the midpoint of one edge to the midpoint of the opposite edge. -
41 Three Dimensional Shapes
41 Three Dimensional Shapes Space figures are the first shapes children perceive in their environment. In elementary school, children learn about the most basic classes of space fig- ures such as prisms, pyramids, cylinders, cones and spheres. This section concerns the definitions of these space figures and their properties. Planes and Lines in Space As a basis for studying space figures, first consider relationships among lines and planes in space. These relationships are helpful in analyzing and defining space figures. Two planes in space are either parallel as in Figure 41.1(a) or intersect as in Figure 41.1(b). Figure 41.1 The angle formed by two intersecting planes is called the dihedral angle. It is measured by measuring an angle whose sides line in the planes and are perpendicular to the line of intersection of the planes as shown in Figure 41.2. Figure 41.2 Some examples of dihedral angles and their measures are shown in Figure 41.3. 1 Figure 41.3 Two nonintersecting lines in space are parallel if they belong to a common plane. Two nonintersecting lines that do not belong to the same plane are called skew lines. If a line does not intersect a plane then it is said to be parallel to the plane. A line is said to be perpendicular to a plane at a point A if every line in the plane through A intersects the line at a right angle. Figures illustrating these terms are shown in Figure 41.4. Figure 41.4 Polyhedra To define a polyhedron, we need the terms ”simple closed surface” and ”polygonal region.” By a simple closed surface we mean any surface with- out holes and that encloses a hollow region-its interior. -
The Fragmentation of Being and the Path Beyond the Void 1555 Copyright 1994 Kent D
DRAFT Fragment 34 AUTOPOIETIC STRUCTURE In this essay, a hypothetical structure of the autopoietic system will be explored. This structure has been alluded to throughout the foregoing metaphysical development of the importance of the autopoietic concept. But it is good to have a purely structural model to refer to in order to develop the metaphysical concepts at a more concrete level of the general architecture of autopoietic systems. This development will depart from the structure given by Plato, and will attempt to give a model that is clearer and more internally coherent, developed from first principles. This is not to say that all autopoietic systems necessarily have this form, but that it is closer to the archetypal form and more clearly of an axiomatic simplicity and purity. It is posited that autopoietic systems may take an unknown variety of forms, and that we are merely giving one which is closest to the threshold of minimality. Much of the contents of this essay owes its insights to work cited earlier on software development methodologies and software development work process. This concrete discipline lent itself to developing these ideas in The Fragmentation of Being and The Path Beyond The Void 1555 Copyright 1994 Kent D. Palmer. All rights reserved. Not for distribution. AUTOPOIETIC STRUCTURE unexpected ways. Some steps toward the position stated here may be found in my series on Software Engineering Foundations and the article on The Future Of Software Process. In the latter article, I attempted to articulate what an autopoietic software process might look like. In the course of developing those ideas and realizing their connection to the work on software design methods, the following approach to defining the autopoietic system arose.