In geometry, the pentagonal orthocupolarotunda is one of the Johnson solids (J32). As the name suggests, it can be constructed by joining a pentagonal cupola (J5) and a pentagonal rotunda (J6) along their decagonal bases, matching the pentagonal faces. A 36-degree rotation of one of the halves before the joining yields a pentagonal gyrocupolarotunda (J33). A Johnson solid is one of 92 strictly convex polyhedra that is composed of regular polygon faces but are not uniform polyhedra (that is, they are not Platonic solids, Archimedean solids, prisms, or antiprisms). They were named by Norman Johnson, who first listed these polyhedra in 1966. (Wikipedia).
Orthocenters exist! | Universal Hyperbolic Geometry 10 | NJ Wildberger
In classical hyperbolic geometry, orthocenters of triangles do not in general exist. Here in universal hyperbolic geometry, they do. This is a crucial building block for triangle geometry in this subject. The dual of an orthocenter is called an ortholine---also not seen in classical hyperb
From playlist Universal Hyperbolic Geometry
How to find the volume of a pentagonal pyramid
👉 Learn how to find the volume and the surface area of a pyramid. A pyramid is a 3-dimensional object having a polygon as its base and triangular surfaces converging at a single point called its apex. A pyramid derives its name from the shape of its base, i.e. a pyramid with a triangular b
From playlist Volume and Surface Area
The Chaos Game in Pentagon, Octagon, and Square (math visualization)
To buy me a coffee, head over to https://www.buymeacoffee.com/VisualProofs Thanks! In this video, we explore the differences between starting with a random dot in a regular pentagon, octagon, and square and iterating the procedure of choosing a vertex (or midpoint for square) at random a
From playlist Fractals
What's a Pentagon? Geometry Terms and Definitions
An introduction to the pentagon, a fundamental geometric shape. Geometer: Louise McCartney Artwork: Kelly Vivanco Director: Michael Harrison Written & Produced by Kimberly Hatch Harrison and Michael Harrison ♦♦♦♦♦♦♦♦♦♦ Ways to support our channel: ► Join our Patreon : https://www.patr
From playlist Socratica: The Geometry Glossary Series
Incenter, Circumcenter, Orthocenter & Centroid of a Triangle - Geometry
This geometry video tutorial explains how to identify the location of the incenter, circumcenter, orthocenter and centroid of a triangle. The incenter can be found be drawing the 3 angle bisectors of a triangle and identifying the point of intersection. The incenter always lie inside of
From playlist Geometry Video Playlist
To construct a PENTAGON with ruler (straightedge) and compass
Geometrical construction of a pentagon with Euclidean Tools Follow me: http://www.twitter.com/dantecardoso
From playlist Math
How to determine if a set of points makes up a rectangle using the distance formula
👉 Learn how to determine the figure given four points. A quadrilateral is a polygon with four sides. Some of the types of quadrilaterals are: parallelogram, square, rectangle, rhombus, kite, trapezoid, etc. Each of the types of quadrilateral has its properties. Given four points that repr
From playlist Quadrilaterals on a Coordinate Plane
Using a set of points determine if the figure is a parallelogram using the midpoint formula
👉 Learn how to determine the figure given four points. A quadrilateral is a polygon with four sides. Some of the types of quadrilaterals are: parallelogram, square, rectangle, rhombus, kite, trapezoid, etc. Each of the types of quadrilateral has its properties. Given four points that repr
From playlist Quadrilaterals on a Coordinate Plane
Orthogonality and Orthonormality
We know that the word orthogonal is kind of like the word perpendicular. It implies that two vectors have an angle of ninety degrees or half pi radians between them. But this term means much more than this, as we can have orthogonal matrices, or entire subspaces that are orthogonal to one
From playlist Mathematics (All Of It)
Ayliean MacDonald - The Pentagon: A User’s Guide - CoM Oct 2021
Regular pentagons throw a spanner in the works when it comes to tessellation but don’t let that one case tarnish the good name of the pentagon! Come along as we explore the 15 irregular pentagons which do tile the plane, journey through five fold symmetry, make a quick pit stop to look at
From playlist Celebration of Mind 2021
Glen Whitney - Convex Pintegon Tilings - CoM Oct 2021
Tiling the plane with convex pentagons has a rich mathematical history in which Martin Gardner and a diverse cast of other participants play key roles. Broad audiences can appreciate the associated questions, and enjoy the beautiful images that the answers yield. All of these characteristi
From playlist Celebration of Mind 2021
D. Davis - Periodic paths on the pentagon
Mathematicians have long understood periodic trajectories on the square billiard table. In the present work, we describe periodic trajectories on the regular pentagon – their geometry, symbolic dynamics, and group structure. Some of the periodic trajectories exhibit a surprising
From playlist Ecole d'été 2018 - Teichmüller dynamics, mapping class groups and applications
Do Facts Matter in Storytelling?
From the mediaX Seminar, Science Storytelling & the Contagion of Ideas, journalist Jamie McIntyre shares how his reporting of the Pentagon attack on 9-11 was taken out of context, and how this event lead him on a decade long journey to try to better understand the limits of factual informa
From playlist Science Storytelling and the Contagion of Ideas
Diana Davis: Billiards on regular polygons
HYBRID EVENT Recorded during the meeting "Differential Geometry, Billiards, and Geometric Optics" the October 04, 2021 by the Centre International de Rencontres Mathématiques (Marseille, France) Filmmaker: Guillaume Hennenfent Find this video and other talks given by worldwide mathemat
From playlist Dynamical Systems and Ordinary Differential Equations
Laura Taalman - Printing Perfect Pentagons - G4G13 Apr 2018
So we know there are 15 families of pentagonal tessellations… how do we 3D print models based on those tessellations?
From playlist G4G13 Videos
Bob Hearn - There Are Only 15 - G4G13 Apr 2018
Notes on the proof that there are only 15 convex pentagons that tile the plane.
From playlist G4G13 Videos
Frank Morgan - Optimal Pentagonal Tilings - CoM May 2021
In 2001 Thomas Hales proved that hexagons provide the least-perimeter way to tile the plane with unit areas. Of course, among hexagons, the regular one is best. Similarly, the best quadrilateral is square and the best triangle is equilateral. But what is the best pentagonal tile? Unfortuna
From playlist Celebration of Mind 2021
A 100 YEAR OLD PROBLEM AND ITS 15 SOLUTIONS: Pentagons and Tiling | ND
Today we look at a 100+ year old problem and its 15 solutions. The 100 year old math problem being the convex monohedral pentagonal tiling problem the only open case of the convex monohedral tiling problem. Pentagons have been a point of interest in the study of tiling for a while due to t
From playlist The New CHALKboard
Determine if a set of points is a trapezoid or not
👉 Learn how to determine the figure given four points. A quadrilateral is a polygon with four sides. Some of the types of quadrilaterals are: parallelogram, square, rectangle, rhombus, kite, trapezoid, etc. Each of the types of quadrilateral has its properties. Given four points that repr
From playlist Quadrilaterals on a Coordinate Plane