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UNITAT 1: FORMES GEOMÈTRIQUES GEOMETRIC SHAPES
EDUCACIÓ VISUAL I PLÀSTICA – 1 ESO
Escola Betúlia - 2014 -2015
Chapter 1
Geometric Shapes
Polígon - Polygon
Side or edges
The segments are called sides or edges
The edges where two segments meet are the polygon’s vertices (sing vertex) or corners
vertex
Cambridge definition: a flat shape with three or more straight sides
Polygon
You can make names using this method:
...end with+1 ...henagon+2 ...digon+3 ...trigon+4 ...tetragon+5 ...pentagon+6 ...hexagon+7 ...heptagon+8 ...octagon+9
Start with...20 Icosi...30 Triaconta...40 Tetraconta...50 Pentaconta...60 Hexaconta...70 Heptaconta...80 Octaconta...90 Enneaconta...100 Hecta...etc..
Example: a 63-sided polygon is a Hexacontadigon
BUT, for polygons with 13 or more sides, it is OK (and easier) to write "13-gon", "14-gon" ... "100-gon", etc.
Regular Polygon
Triangle
A plane figure with three straight sides and three angles
A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry.
Equilateral Isosceles Scalene
Quadrilateral
A quadrilateral is a polygon with four sides (or edges) and four vertices or corners.
Simple quadrilateral Complex quadrilateral
Quadrilateral
The interior angles of a simple (and planar) quadrilateral ABCD add up to 360 degrees of arc, that is
Pentagon
A pentagon is any five-sided polygon. A pentagon may be simple or self-intersecting. The sum of the internal angles in a simple pentagon is 540°.
A pentagram is an example of a self-intersecting pentagon.
A regular pentagon, all sides are equal in length and each interior angle is 108°
Polyhedron
A polyhedron (plural polyhedra or polyhedrons) is a solid in three dimensions with flat faces, straight edges and sharp corners or vertices (singular: vertex).
face
edge
Corner or vertex
Regular Polyhedron
Tetrahedron Hexahedron Octahedron Dodecahedron Icosahedron
3 faces 4 faces 8 faces 12 faces 20 faces
Known as the Platonic solids
Regular Polyhedron
Small stellated dodecahedron
Great dodecahedron
Great stellated dodecahedron
Great icosahedron
12 pentagrammic
faces
12 pentagonal faces
12 intersecting pentagrammic faces
20 intersecting triangular faces
Known as the Kepler-Poinsot polyhedra
Pentagons in polyhedra
Dodecahedron Pyritohedron Pentagonal icositetrahedron
Pentagonal hexecontahedron
Truncated_trapezohedron
Archimedean solidAn Archimedean solid is a highly symmetric, semi-regular convex polyhedron composed of two or more types of regular polygons meeting in identical vertices
Truncated tetrahedron
Cuboctahedron Truncated hexahedron
Truncated octahedron
Small rhombicuboctahedron
Great rhombicuboctahedron
Snub hexahedron Icosidodecahedron Truncated
dodecahedronTruncated
icosahedron
4 triangles4 hexagons
8 triangles6 squares 8 triangles
6 octagons6 squares
8 hexagons
8 triangles18 squares
12 squares8 hexagons6 octagons
32 triangles6 squares
20 triangles12 pentagons 20 triangles
12 decagons12 pentagons20 hexagons
Archimedean solid
Small rhombicosidodecahedron
Great rhombicosidodecahedron
Snub dodecahedron
20 triangles30 squares
12 pentagons
30 squares20 hexagons12 decagons
8 triangles6 octagons