Equilateral Triangle Examples in Real Life
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Square Rectangle Triangle Diamond (Rhombus) Oval Cylinder Octagon Pentagon Cone Cube Hexagon Pyramid Sphere Star Circle
SQUARE RECTANGLE TRIANGLE DIAMOND (RHOMBUS) OVAL CYLINDER OCTAGON PENTAGON CONE CUBE HEXAGON PYRAMID SPHERE STAR CIRCLE Powered by: www.mymathtables.com Page 1 what is Rectangle? • A rectangle is a four-sided flat shape where every angle is a right angle (90°). means "right angle" and show equal sides. what is Triangle? • A triangle is a polygon with three edges and three vertices. what is Octagon? • An octagon (eight angles) is an eight-sided polygon or eight-gon. what is Hexagon? • a hexagon is a six-sided polygon or six-gon. The total of the internal angles of any hexagon is 720°. what is Pentagon? • a plane figure with five straight sides and five angles. what is Square? • a plane figure with four equal straight sides and four right angles. • every angle is a right angle (90°) means "right ang le" show equal sides. what is Rhombus? • is a flat shape with four equal straight sides. A rhombus looks like a diamond. All sides have equal length. Opposite sides are parallel, and opposite angles are equal what is Oval? • Many distinct curves are commonly called ovals or are said to have an "oval shape". • Generally, to be called an oval, a plane curve should resemble the outline of an egg or an ellipse. Powered by: www.mymathtables.com Page 2 What is Cube? • Six equal square faces.tweleve edges and eight vertices • the angle between two adjacent faces is ninety. what is Sphere? • no faces,sides,vertices • All points are located at the same distance from the center. what is Cylinder? • two circular faces that are congruent and parallel • faces connected by a curved surface. -
Applying the Polygon Angle
POLYGONS 8.1.1 – 8.1.5 After studying triangles and quadrilaterals, students now extend their study to all polygons. A polygon is a closed, two-dimensional figure made of three or more non- intersecting straight line segments connected end-to-end. Using the fact that the sum of the measures of the angles in a triangle is 180°, students learn a method to determine the sum of the measures of the interior angles of any polygon. Next they explore the sum of the measures of the exterior angles of a polygon. Finally they use the information about the angles of polygons along with their Triangle Toolkits to find the areas of regular polygons. See the Math Notes boxes in Lessons 8.1.1, 8.1.5, and 8.3.1. Example 1 4x + 7 3x + 1 x + 1 The figure at right is a hexagon. What is the sum of the measures of the interior angles of a hexagon? Explain how you know. Then write an equation and solve for x. 2x 3x – 5 5x – 4 One way to find the sum of the interior angles of the 9 hexagon is to divide the figure into triangles. There are 11 several different ways to do this, but keep in mind that we 8 are trying to add the interior angles at the vertices. One 6 12 way to divide the hexagon into triangles is to draw in all of 10 the diagonals from a single vertex, as shown at right. 7 Doing this forms four triangles, each with angle measures 5 4 3 1 summing to 180°. -
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. -
Polygrams and Polygons
Poligrams and Polygons THE TRIANGLE The Triangle is the only Lineal Figure into which all surfaces can be reduced, for every Polygon can be divided into Triangles by drawing lines from its angles to its centre. Thus the Triangle is the first and simplest of all Lineal Figures. We refer to the Triad operating in all things, to the 3 Supernal Sephiroth, and to Binah the 3rd Sephirah. Among the Planets it is especially referred to Saturn; and among the Elements to Fire. As the colour of Saturn is black and the Triangle that of Fire, the Black Triangle will represent Saturn, and the Red Fire. The 3 Angles also symbolize the 3 Alchemical Principles of Nature, Mercury, Sulphur, and Salt. As there are 3600 in every great circle, the number of degrees cut off between its angles when inscribed within a Circle will be 120°, the number forming the astrological Trine inscribing the Trine within a circle, that is, reflected from every second point. THE SQUARE The Square is an important lineal figure which naturally represents stability and equilibrium. It includes the idea of surface and superficial measurement. It refers to the Quaternary in all things and to the Tetrad of the Letter of the Holy Name Tetragrammaton operating through the four Elements of Fire, Water, Air, and Earth. It is allotted to Chesed, the 4th Sephirah, and among the Planets it is referred to Jupiter. As representing the 4 Elements it represents their ultimation with the material form. The 4 angles also include the ideas of the 2 extremities of the Horizon, and the 2 extremities of the Median, which latter are usually called the Zenith and the Nadir: also the 4 Cardinal Points. -
Symmetry Is a Manifestation of Structural Harmony and Transformations of Geometric Structures, and Lies at the Very Foundation
Bridges Finland Conference Proceedings Some Girihs and Puzzles from the Interlocks of Similar or Complementary Figures Treatise Reza Sarhangi Department of Mathematics Towson University Towson, MD 21252 E-mail: [email protected] Abstract This paper is the second one to appear in the Bridges Proceedings that addresses some problems recorded in the Interlocks of Similar or Complementary Figures treatise. Most problems in the treatise are sketchy and some of them are incomprehensible. Nevertheless, this is the only document remaining from the medieval Persian that demonstrates how a girih can be constructed using compass and straightedge. Moreover, the treatise includes some puzzles in the transformation of a polygon into another one using mathematical formulas or dissection methods. It is believed that the document was written sometime between the 13th and 15th centuries by an anonymous mathematician/craftsman. The main intent of the present paper is to analyze a group of problems in this treatise to respond to questions such as what was in the mind of the treatise’s author, how the diagrams were constructed, is the conclusion offered by the author mathematically provable or is incorrect. All images, except for photographs, have been created by author. 1. Introduction There are a few documents such as treatises and scrolls in Persian mosaic design, that have survived for centuries. The Interlocks of Similar or Complementary Figures treatise [1], is one that is the source for this article. In the Interlocks document, one may find many interesting girihs and also some puzzles that are solved using mathematical formulas or dissection methods. Dissection, in the present literature, refers to cutting a geometric, two-dimensional shape, into pieces that can be rearranged to compose a different shape. -
Petrie Schemes
Canad. J. Math. Vol. 57 (4), 2005 pp. 844–870 Petrie Schemes Gordon Williams Abstract. Petrie polygons, especially as they arise in the study of regular polytopes and Coxeter groups, have been studied by geometers and group theorists since the early part of the twentieth century. An open question is the determination of which polyhedra possess Petrie polygons that are simple closed curves. The current work explores combinatorial structures in abstract polytopes, called Petrie schemes, that generalize the notion of a Petrie polygon. It is established that all of the regular convex polytopes and honeycombs in Euclidean spaces, as well as all of the Grunbaum–Dress¨ polyhedra, pos- sess Petrie schemes that are not self-intersecting and thus have Petrie polygons that are simple closed curves. Partial results are obtained for several other classes of less symmetric polytopes. 1 Introduction Historically, polyhedra have been conceived of either as closed surfaces (usually topo- logical spheres) made up of planar polygons joined edge to edge or as solids enclosed by such a surface. In recent times, mathematicians have considered polyhedra to be convex polytopes, simplicial spheres, or combinatorial structures such as abstract polytopes or incidence complexes. A Petrie polygon of a polyhedron is a sequence of edges of the polyhedron where any two consecutive elements of the sequence have a vertex and face in common, but no three consecutive edges share a commonface. For the regular polyhedra, the Petrie polygons form the equatorial skew polygons. Petrie polygons may be defined analogously for polytopes as well. Petrie polygons have been very useful in the study of polyhedra and polytopes, especially regular polytopes. -
Right Triangles and the Pythagorean Theorem Related?
Activity Assess 9-6 EXPLORE & REASON Right Triangles and Consider △ ABC with altitude CD‾ as shown. the Pythagorean B Theorem D PearsonRealize.com A 45 C 5√2 I CAN… prove the Pythagorean Theorem using A. What is the area of △ ABC? Of △ACD? Explain your answers. similarity and establish the relationships in special right B. Find the lengths of AD‾ and AB‾ . triangles. C. Look for Relationships Divide the length of the hypotenuse of △ ABC VOCABULARY by the length of one of its sides. Divide the length of the hypotenuse of △ACD by the length of one of its sides. Make a conjecture that explains • Pythagorean triple the results. ESSENTIAL QUESTION How are similarity in right triangles and the Pythagorean Theorem related? Remember that the Pythagorean Theorem and its converse describe how the side lengths of right triangles are related. THEOREM 9-8 Pythagorean Theorem If a triangle is a right triangle, If... △ABC is a right triangle. then the sum of the squares of the B lengths of the legs is equal to the square of the length of the hypotenuse. c a A C b 2 2 2 PROOF: SEE EXAMPLE 1. Then... a + b = c THEOREM 9-9 Converse of the Pythagorean Theorem 2 2 2 If the sum of the squares of the If... a + b = c lengths of two sides of a triangle is B equal to the square of the length of the third side, then the triangle is a right triangle. c a A C b PROOF: SEE EXERCISE 17. Then... △ABC is a right triangle. -
Cyclic Quadrilaterals — the Big Picture Yufei Zhao [email protected]
Winter Camp 2009 Cyclic Quadrilaterals Yufei Zhao Cyclic Quadrilaterals | The Big Picture Yufei Zhao [email protected] An important skill of an olympiad geometer is being able to recognize known configurations. Indeed, many geometry problems are built on a few common themes. In this lecture, we will explore one such configuration. 1 What Do These Problems Have in Common? 1. (IMO 1985) A circle with center O passes through the vertices A and C of triangle ABC and intersects segments AB and BC again at distinct points K and N, respectively. The circumcircles of triangles ABC and KBN intersects at exactly two distinct points B and M. ◦ Prove that \OMB = 90 . B M N K O A C 2. (Russia 1995; Romanian TST 1996; Iran 1997) Consider a circle with diameter AB and center O, and let C and D be two points on this circle. The line CD meets the line AB at a point M satisfying MB < MA and MD < MC. Let K be the point of intersection (different from ◦ O) of the circumcircles of triangles AOC and DOB. Show that \MKO = 90 . C D K M A O B 3. (USA TST 2007) Triangle ABC is inscribed in circle !. The tangent lines to ! at B and C meet at T . Point S lies on ray BC such that AS ? AT . Points B1 and C1 lies on ray ST (with C1 in between B1 and S) such that B1T = BT = C1T . Prove that triangles ABC and AB1C1 are similar to each other. 1 Winter Camp 2009 Cyclic Quadrilaterals Yufei Zhao A B S C C1 B1 T Although these geometric configurations may seem very different at first sight, they are actually very related. -
Cyclic Quadrilaterals
GI_PAGES19-42 3/13/03 7:02 PM Page 1 Cyclic Quadrilaterals Definition: Cyclic quadrilateral—a quadrilateral inscribed in a circle (Figure 1). Construct and Investigate: 1. Construct a circle on the Voyage™ 200 with Cabri screen, and label its center O. Using the Polygon tool, construct quadrilateral ABCD where A, B, C, and D are on circle O. By the definition given Figure 1 above, ABCD is a cyclic quadrilateral (Figure 1). Cyclic quadrilaterals have many interesting and surprising properties. Use the Voyage 200 with Cabri tools to investigate the properties of cyclic quadrilateral ABCD. See whether you can discover several relationships that appear to be true regardless of the size of the circle or the location of A, B, C, and D on the circle. 2. Measure the lengths of the sides and diagonals of quadrilateral ABCD. See whether you can discover a relationship that is always true of these six measurements for all cyclic quadrilaterals. This relationship has been known for 1800 years and is called Ptolemy’s Theorem after Alexandrian mathematician Claudius Ptolemaeus (A.D. 85 to 165). 3. Determine which quadrilaterals from the quadrilateral hierarchy can be cyclic quadrilaterals (Figure 2). 4. Over 1300 years ago, the Hindu mathematician Brahmagupta discovered that the area of a cyclic Figure 2 quadrilateral can be determined by the formula: A = (s – a)(s – b)(s – c)(s – d) where a, b, c, and d are the lengths of the sides of the a + b + c + d quadrilateral and s is the semiperimeter given by s = 2 . Using cyclic quadrilaterals, verify these relationships. -
Tilings Page 1
Survey of Math: Chapter 20: Tilings Page 1 Tilings A tiling is a covering of the entire plane with ¯gures which do not not overlap, and leave no gaps. Tilings are also called tesselations, so you will see that word often. The plane is in two dimensions, and that is where we will focus our examination, but you can also tile in one dimension (over a line), in three dimensions (over a space) and mathematically, in even higher dimensions! How cool is that? Monohedral tilings use only one size and shape of tile. Regular Polygons A regular polygon is a ¯gure whose sides are all the same length and interior angles are all the same. n 3 n 4 n 5 n 6 n 7 n 8 n 9 Equilateral Triangle, Square, Pentagon, Hexagon, n-gon for a regular polygon with n sides. Not all of these regular polygons can tile the plane. The regular polygons which do tile the plane create a regular tiling, and if the edge of a tile coincides entirely with the edge of a bordering tile, it is called an edge-to-edge tiling. Triangles have an edge to edge tiling: Squares have an edge to edge tiling: Pentagons don't have an edge to edge tiling: Survey of Math: Chapter 20: Tilings Page 2 Hexagons have an edge to edge tiling: The other n-gons do not have an edge to edge tiling. The problem with the ones that don't (pentagon and n > 6) has to do with the angles in the n-gon. -
The Order in Creation in Number and Geometry
THE ORDER IN CREATION IN NUMBER AND GEOMETRY Tontyn Hopman www.adhikara.com/number_and_geometry.html Illustrations by the author 2 About the origin of “The Order in Creation in Number and Geometry”. The author, Frederik (Tontyn) Hopman, was born in Holland in 1914, where he studied to become an architect. At the age of 18, after the death of his father, he had a powerful experience that led to his subsequent study of Oriental esoteric teachings. This was to become a life-long fascination. Responding to the call of the East, at the age of 21, he travelled to India by car. In those days this adventurous journey took many weeks. Once in India he married his travelling companion and settled down in Kashmir, where he lived with his young family for 12 years until in 1947 the invasion from Pakistan forced them to flee. Still in Asia, at the age of 38, Tontyn Hopman had a profound Kundalini awakening that gave his life a new dimension. It was during this awakening that he had a vision of Genesis, which revealed to him the ‘Order in Creation in Number and Geometry’. Around this time, however, Tontyn Hopman decided to return to Europe to enable his children to have a good education and he settled in Switzerland to practise his profession as an architect. Later he occupied himself with astrology and art therapy. Here, in Switzerland, after almost half a century, the memory of his vision came up again, with great clarity. Tontyn Hopman experienced a strong impulse to work on, and present the images that had been dormant for such a long time to the wider public. -
Dissecting and Folding Stacked Geometric Figures
Dissecting and Folding Stacked Geometric Figures Greg N. Frederickson Purdue University Copyright notice: Permission is granted only to DIMACS to post this copy of Greg N. Frederickson’s talk, “Dissecting and Folding Stacked Geometric Figures”, on its website. No permission is granted for others to copy any portions of this talk for their own or anyone else’s use. If you have what you feel is a justifiable use of this talk, contact me ( [email protected] ) to ask permission. Because producing this material was a lot of work, I reserve the right to deny any particular request. 1 A note about animations and videos None of the animations and videos were included when my powerpoint file was converted to a pdf file. Any slide that contains a picture with color but no title is the first frame of an animation or video. Selected animations are available from my webpages: http://www.cs.purdue.edu/homes/gnf/book3/stackfold.html http://www.cs.purdue.edu/homes/gnf/book3/stackfold2.html These animations were time-intensive to produce. Please show your appreciation by respecting my copyright. Dissection of one square to two squares [Plato, 4 th century, BCE] 2 Hinged dissection of one square to two squares (with 2 swing-hinged assemblages) Piano-hinge (fold-hinge) brings a piece A from being next to a piece B to being on top of B 3 Piano-hinged dissection of 1 square to 2 squares (with 2 assemblages) 4 Juggling 2 (or more) assemblages is a pain! So let’s change the game: Instead of having two smaller squares, let’s have just one , but twice as high.