{VERSION 5 0 "IBM INTEL NT" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{CSTYLE "" -1 256 "" 0 1 0 128 0 1 0 0 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 257 "" 0 1 0 128 0 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 258 "" 0 1 0 128 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 259 "" 0 1 128 128 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 260 "" 0 1 0 0 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 261 "" 0 1 0 0 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 262 "" 0 1 0 0 128 1 0 0 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 263 "" 0 1 0 0 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 264 "" 0 1 0 0 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 265 "" 0 1 0 0 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 266 "" 0 1 0 0 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 267 "" 0 1 0 128 0 1 0 0 0 0 0 0 0 0 0 0 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 2 2 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "Heading 1" -1 3 1 {CSTYLE "" -1 -1 "Times" 1 18 0 0 0 1 2 1 2 2 2 2 1 1 1 1 }1 1 0 0 8 4 1 0 1 0 2 2 0 1 }{PSTYLE "Heading 2" -1 4 1 {CSTYLE "" -1 -1 "Time s" 1 14 0 0 0 1 2 1 2 2 2 2 1 1 1 1 }1 1 0 0 8 2 1 0 1 0 2 2 0 1 } {PSTYLE "Normal" -1 256 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 1 2 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }} {SECT 0 {PARA 0 "" 0 "" {TEXT -1 0 "" }{TEXT 257 50 "High School Modul es > Geometry by Gregory A. Moore" }{TEXT 267 1 "\n" }}{PARA 3 "" 0 " " {TEXT -1 4 " " }{TEXT 256 24 "Regular Polygons & Stars" }}{PARA 0 "" 0 "" {TEXT -1 161 "\nAn exploration of regular polygons and their features - including graphs of the different types of axes of symmetr y, and a peek at stars of the geometry world.\n" }}{PARA 0 "" 0 "" {TEXT 258 153 "[Directions : Execute the Code Resource section first. \+ Although there will be no output immediately, these definitions are us ed later in this worksheet.]" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 1 " " }{TEXT 260 7 "0. Code" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 38 "restart; with(plots): with(geometry ): " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 499 "sbl := 'axes = none , scaling = constrained, \n thickness = 3, color = COLOR(RGB, \+ .5,.4,.8)':\nsgy := 'axes = none, scaling = constrained, \n th ickness = 3, color = COLOR(RGB, .5,.5,.6)':\nsbe := 'axes = none, sc aling = constrained, \n thickness = 3, color = COLOR(RGB, .8,.7, .5)':\nsor := 'axes = none, scaling = constrained, \n thicknes s = 3, color = COLOR(RGB, .9,.7,.1)':\nsgn := 'axes = none, scaling \+ = constrained, \n thickness = 3, color = COLOR(RGB, .4,.7,.4)': " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 233 "cbl := 'color = COLOR( RGB, .5,.4,.8)':\ncgy := 'color = COLOR(RGB, .5,.5,.6)':\ncbe := 'colo r = COLOR(RGB, .8,.7,.5)':\ncor := 'color = COLOR(RGB, .9,.7,.1)':\ncy l := 'color = COLOR(RGB, .9,.8,.1)':\ncgn := 'color = COLOR(RGB, .5,.8 ,.5)':" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 173 "scanft := 'scali ng = constrained, axes = none':\nscanft := 'filled = true, axes = none , scaling = constrained':\nscant2 := 'thickness = 2, axes = none, scal ing = constrained':" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 33 "point(o,0,0);\ncircle( UC ,[ o,1]):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 291 "RegPolyPlot := \+ proc( N )\n local k, n, ngon, c;\n ngon := n -> [seq([ cos(2*Pi*i/n ), sin(2*Pi*i/n) ], i = 1..n)]: \n c := n -> COLOR(RGB, .2+n/(2*N), \+ .2+n/(2*N), .5);\n display([ seq( polygonplot(ngon(n), color=c(n)), n = 3..N)],\n scaling = constrained, axes = none);\nend proc: \n" }}}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 1 " " }{TEXT 262 11 "1. Polyg ons" }}{PARA 0 "" 0 "" {TEXT -1 67 "\nA polygon is a any simple closed shape formed with line segments.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 53 "plot( [ [0,0],[2,0],[3,5],[1,4],[-2,1],[0,0]], sgy ); " }}}{PARA 0 "" 0 "" {TEXT -1 46 "\n\nSome familiar polygons include t riangles ..." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 220 "display( pl ot( [ [3,0],[7,0],[5,6],[3,0]], sgy ),\n plot( [ [-7,5],[-5,7] ,[-2,5],[-7,5]], sbe ), \n plot( [ [-5,3],[3,3],[3,6],[-5,3]], sor ), \n plot( [ [-6,0],[-1,0],[-8,2],[-6,0]], sgn ) \+ );" }}}{PARA 0 "" 0 "" {TEXT -1 29 "\n\nSqaures and rectangles ...." } }{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 244 "display( plot( [ [3,0],[7, 0],[7,6],[3,6],[3,0]], sgy ),\n plot( [ [-5,1],[5,1],[5,3],[-5 ,3],[-5,1]], sgn ),\n plot( [ [2,2],[4,2],[4,4],[2,4],[2,2]], \+ sor ),\n plot( [ [-7,5],[-7,2],[-2,2],[-2,5],[-7,5]], sbe ) \n );" }}}{PARA 0 "" 0 "" {TEXT -1 21 "\n But there are more!" }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 1 " " }{TEXT 263 19 "2. Regular Po lygons" }}{PARA 0 "" 0 "" {TEXT -1 150 "\nRegular polygons are polygon s where all the sides are equal and all the interior angles are equal. A five sided regular polygon is called a pentagon." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 70 "RegularPolygon( RegPoly,5,o,1):\ndisplay( d raw(RegPoly, scanft, cbl ));" }}}{PARA 0 "" 0 "" {TEXT -1 39 "\nAll re gular polygons fit into circles." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 61 "display( draw(UC, scant2, cbe), draw(RegPoly, scanft, cbl )); " }}}{PARA 0 "" 0 "" {TEXT -1 40 "\nHere are the details of this penta gon. " }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "detail(RegPoly);" } }}{PARA 0 "" 0 "" {TEXT -1 108 "\nAlthough it requires some translatio n, what it is saying is that the interior angles are this many degrees ." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "(3/5)*Pi*(180/Pi);" }}} {PARA 0 "" 0 "" {TEXT -1 58 "\n\nHere are some other regular polygons. Can you name them?" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 111 "Regu larPolygon( RegPoly ,3,o,1):\ndisplay( draw(UC, scant2, cbe), draw(Reg Poly, scanft, cgy ));\ndetail(RegPoly);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 111 "RegularPolygon( RegPoly ,6,o,1):\ndisplay( draw(UC, \+ scant2, cbe), draw(RegPoly, scanft, cgn ));\ndetail(RegPoly);" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 119 "RegularPolygon( RegPoly ,8, o,1):\ndisplay( draw(UC, scant2, color=black), draw(RegPoly, scanft, c or ));\ndetail(RegPoly);" }}}{PARA 0 "" 0 "" {TEXT -1 252 "\nHere is a regular 17-sided polygon, which has some historical significance (aft er find the first construction of such a polygon, a young Gauss decide d on a very fruitful life in mathematics). Notice how close it is to t he circle that circumscribes it." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 112 "RegularPolygon( RegPoly ,17,o,1):\ndisplay( draw(UC, scant2, \+ cbe), draw(RegPoly, scanft, cbl ));\ndetail(RegPoly);" }}}{PARA 0 "" 0 "" {TEXT -1 209 "\n\n\nIf we draw a number of regular polygons on th e same diagram we can see the progression. Here are regular polygons w ith 3 to 10 sides, and then 3 to 30 sides. They seem to fill the unit \+ circle more and more." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "Reg PolyPlot(6);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "RegPolyPlot (10);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "RegPolyPlot(25);" }}}{PARA 0 "" 0 "" {TEXT -1 2 "\n " }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 1 " " }{TEXT 266 30 "3. Interior Angles of Polygons" }}{PARA 0 "" 0 "" {TEXT -1 124 "\nWe know that the sum of the angles of a triangle \+ is 180 degrees, and rectangle (or any four sided polygon) is 360 degre es.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "n := 3; total_int_a ngles := 180;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "n := 4; to tal_int_angles := 360;" }}}{PARA 0 "" 0 "" {TEXT -1 30 "\nActually the re is a formula :" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 33 "total_i nterior := n -> 180*(n-2);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 135 "A := array( [seq( [ n, total_interior(n) ], n = 2..10) ]):\nA[1 ,1] := `Number of sides`: \nA[1,2] := `Total Interior Angles`:\nprint( A);" }}}{PARA 0 "" 0 "" {TEXT -1 2 "\n " }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 1 " " }{TEXT 264 32 "4. Perimeter of Regular Polygons" }} {PARA 0 "" 0 "" {TEXT -1 113 "\nIf we there is a regular polygon with \+ 10 sides, and each side is 3 feet long, the perimeter is easy to compu te.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 5 "10*3;" }}}{PARA 0 " " 0 "" {TEXT -1 282 "\n On the other hand, if we have a regular polygo n with 7 sides, and the distance from the center to any of the vertice s is 5 feet, how long is the perimeter? This is a problem that can not be answered adequately until you take trigonometry, but we can use Ma ple to find the answer.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 88 "RegularPolygon( RegPoly ,7,o,5):\ndisplay( draw(RegPoly, scanft, cgy \+ ));\ndetail(RegPoly);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "P \+ = evalf( 70*sin(Pi/7), 20);" }}}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 1 " \+ " }{TEXT 265 27 "5. Area of Regular Polygons" }}{PARA 0 "" 0 "" {TEXT -1 70 "\nA regular polygon with n sides can be cut into n isocoles tri angles.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 262 "RegularPolygon ( RegPoly ,7,o,1):\npoint(A,[cos(2*Pi/7), sin(2*Pi/7)]);\npoint(B,[cos (4*Pi/7), sin(4*Pi/7)]);\npoint(C,[cos(3*Pi/7)*cos(Pi/7), sin(3*Pi/7)* cos(Pi/7)]);\nsegment( rad1, [o, A]); \nsegment( rad2, [o, B]); \nsegm ent( h, [o, C]);\nsegment( side, [A,B]); \n \n\n" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 311 "display( draw( \n [ UC(thickness=1, cbe), RegPoly(thickness=2,cgn),\n rad1(color=red,thickness \+ = 2), \n rad2(color=gold, linestyle = 3),\n h(th ickness = 2, color = coral), \n side(thickness = 3, color = green)\n ]), axes=none, scaling=constrained );" }}} {PARA 0 "" 0 "" {TEXT -1 277 "\nYou need three pieces of information : \n 1. n, the number of sides\n 2. the height of each tri angle (the solid yellow/orange line in the middle of the triangle)\n \+ 3. the length of one side of the polygon.\n\nWe can get this fro m the detail command ....\n \n " }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "detail(RegPoly);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 43 "Area = 7*sin(Pi/7)*cos(Pi/7): evalf(%, 50);" }}}} {SECT 0 {PARA 4 "" 0 "" {TEXT -1 1 " " }{TEXT 261 8 "6. Stars" }} {PARA 0 "" 0 "" {TEXT -1 182 "\nAnother type of polygon, which is not \+ \"regular\", but is symetrical, is a \"star\" - a shape not usually co vered in geometry books, but certainly common in artwork and national \+ flags.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 106 "RegularStarPoly gon( star,5/2,o,2):\ndraw(star,filled = true, axes = none,scaling=cons trained,color=orange);" }}}{PARA 0 "" 0 "" {TEXT -1 253 "\nNotice that a star fits nicely within a regular polygon. A 5 sided star fits int o a a regular 5 sided polygon. Also, if you cut off the five points as the vertices closest to the center, you will see that there is anothe r pentagon inside the star too!" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 168 "RegularPolygon( P2,5,o,2):\nRegularStarPolygon( star,5/2,o,2) :\ndraw( [P2(color=coral), star(color = red, filled = true)], \n \+ axes = none, scaling = constrained);" }}}{PARA 0 "" 0 "" {TEXT -1 45 "\nOf course stars can come in other sizes too." }}{EXCHG {PARA 0 " > " 0 "" {MPLTEXT 1 0 122 "RegularStarPolygon( star,9/2,o,1):\ndraw(st ar, \n filled = true, axes = none, scaling = constrained, colo r=sienna );" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{PARA 0 "" 0 "" {TEXT -1 2 "\n " }}}{PARA 0 "" 0 "" {TEXT 259 36 "\n \+ \251 2002 Waterloo Maple Inc " }}}{MARK "0 1" 26 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }