The Pythagorean Theorem - Educational Outreach

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2 :Set up and solve two proportional relationshipsAEABEDCDAD AEAEAD EDED22 AB AD & CD AD3 : Add the two results above and simplify to complete theproof.AEAE22 ED ED22 AB AD CD AD AD AB CDKurrah’s Theorem can be used to prove the Pythagorean0Theorem for the special case 90 via the following verysimple logic sequence.For, if the angle happens to be a right angle, then wehave a merging of the line segment EB with the linesegment EC . This in turn implies that the line segmentBC has zero length andKurrah’s result gives2AB CD AD2AE ED AD ,Note: Yet another proof of the Pythagorean Theorem!***2. Substituting intoMathew Stewart (1717-1785) was a professor at theUniversity of Edinburgh and a Fellow of the Royal Society.The famous theorem as stated on the next page—althoughattributed to Stewart—has geometric similarities totheorems originally discovered and proved by Apollonius.112
Some historians believe Stewart’s Theorem can be traced asfar back as Archimedes. Other historians believe thatSimpson (one of Stewart’s academic mentors) actuallyproved ‘Stewart’s Theorem’. Controversy aside, Stewart wasa brilliant geometer in his own right. Like Euclid, Stewartwas an expert organizer of known and useful results in theburgeoning new area of mathematical physics—especiallyorbital mechanics.Unlike the three previous theorems, Stewart’sTheorem is not co-equal to the Pythagorean Theorem. Thismeans that Stewart’s Theorem requires the use of thePythagorean Theorem in order to construct a proof.Independent proofs of Stewart’s Theorem are not possibleand, thus, any attempt to prove the Pythagorean Theoremusing Stewart’s Theorem becomes an exercise in circularlogic. We now proceed with the theorem statementmad hx nc m nbFigure 3.14: Diagram for Stewart’s TheoremStewart’s Theorem: Suppose a general triangle (atriangle having no special angles such as right angles) hassides with lengths a , b , and c . Let a line segment ofunknown length d be drawn from the vertex of the triangleto the horizontal side as shown in Figure 3.14, cutting cinto two portions m and n where c m n . Then, thefollowing relationship holds among the six line segmentswhose lengths arena2a , b,c,d,m , and n :2 2 mb c[d mn].113
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The PythagoreanTheoremCrown Jewel o
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The Pythagorean TheoremCrown Jewel
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Table of ContentsList of Tables and
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List of Tables and FiguresTablesNum
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Figures…continuedNumber and Title
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List of Proofs and DevelopmentsSect
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PrefaceThe Pythagorean Theorem has
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1 : 2x2x2****22 13x 7 13x 7 0 : a
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1) Consider the Squares“If it was
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s090045 0ss45450450090Figure 1.3: O
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Notice that the right-triangle prop
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The middle square (minus the donut
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Our proof in Chapter 1 has been by
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2) Four Thousand Years of Discovery
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The proof Pythagoras is thought to
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cabcFigure 2.4: Annotated Square wi
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Figure 2.6 is the diagram for a sec
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1x:b2:Area(CBA)3:Area( ABC)Area(ABC
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Euclid’s proof of the Pythagorean
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First we establish that the two tri
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1 2y b b: y b c c2:A3:A4:Aunshaded
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XB'A090 CBFigure 2.12: Euclid’s C
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2.3) Liu Hui Packs the SquaresLiu H
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One of my favorites was Boxel, a ga
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2.4) Kurrah Transforms the Bride’
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Note: as is the occasional custom i
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2.5) Bhaskara Unleashes the Power o
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2.6) Leonardo da Vinci’s Magnific
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In Figure 2.24, we enlarge Step 5 a
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But, this is precisely the nature o
Page 63 and 64: 2.8) Henry Perigal’s TombstoneHen
Page 65 and 66: In the century following Perigal, b
Page 67 and 68: Returning to Henry Perigal, Figure
Page 69 and 70: Figure 2.32 is President Garfield
Page 71 and 72: Even though the Cartesian coordinat
Page 73 and 74: B 2← γ →α y βx C-xC 2Figure
Page 75 and 76: Being polynomial in form, the funct
Page 77 and 78: Thus, the critical point ( C 2 ,0)i
Page 79 and 80: Sincexcpwas chosen on an arbitrary
Page 81 and 82: ∂F/∂x = ∂F/∂y = 0x(C - x) 2
Page 83 and 84: Define a new function21 A2 A3 2xcp
Page 85 and 86: 2.11) Shear, Shape, and AreaOur las
Page 87 and 88: Step 1: Cut the big square into two
Page 89 and 90: In Table 2.3, we briefly summarize
Page 91 and 92: We can formally state this similari
Page 93 and 94: What we will do in Section 3.2 is p
Page 95 and 96: There are three Pythagorean-triple
Page 97 and 98: Thus, if we multiply any given prim
Page 99 and 100: The last equality shows that the in
Page 101 and 102: A Pythagorean Quartet is a set of f
Page 103 and 104: 3.5) Pythagoras and the Three Means
Page 105 and 106: yxy MHxab2ab2 y x FC y ab2ab 2ab y
Page 107 and 108: Hero was the founder of the Higher
Page 109 and 110: 5 : Solve for area using the formul
Page 111 and 112: 4 : Construct the parallelogram wit
Page 113: We already have introduced Thabit i
Page 117 and 118: In pre-computer days, both all four
Page 119 and 120: One example of a periodic process i
Page 121 and 122: The six trigonometric functions are
Page 123 and 124: The following four relationships ar
Page 125 and 126: As with any set of identities, the
Page 127 and 128: Figure 3.17 can be used as a jumpin
Page 129 and 130: The remaining two pillars are the L
Page 131 and 132: a2Law of Cosines c2 b2 2bccos()The
Page 133 and 134: An example of a Diophantine equatio
Page 136 and 137: However, Euler’s Conjecture did n
Page 138 and 139: 4) Pearls of Fun and WonderPearls o
Page 140 and 141: We have achieved five-digit accurac
Page 142 and 143: 140212213116)74370116)(74370(370)74
Page 144 and 145: X X X X O X X O X XO X X O O OO X O
Page 146 and 147: 4.3) Earth, Moon, Sun, and StarsIn
Page 148 and 149: The four-step solution follows. All
Page 150 and 151: Figure 4.9 depicts Eratosthenes’
Page 152 and 153: ---High above the earth, we see the
Page 154 and 155: The commonly accepted value is abou
Page 156 and 157: 1BC : tan( BAC)BABC BAtan(BAC)0BC
Page 158 and 159: BD ACtan( 21 )Even for the closest
Page 160 and 161: 3w 2h s w 5 s w 0.38196s&5 1s
Page 162 and 163: Figure 4.16: Triangular Phi---The h
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What remains to be done is to devel
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3 : h32 4 h222 2 24C 2 h33162 2 2
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Epilogue: The Crown and the Jewels
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Not only has it endured, but the Py
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A] Greek AlphabetGREEK LETTERUpper
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C] Geometric FoundationsThe Paralle
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8. Congruent Triangles: Two triangl
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3. Rectangle: A bh : P 2b 2h, b &
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Recreational Mathematics11. Pickove
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GGolden RatioDefined and algebraica
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Puzzles (cont)Pythagorean Magic Squ
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Pythagorean Theorem ProofsAlgebraic
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Trigonometry (cont)Eratosthenes mea
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The Pythagorean Theorem - Educational Outreach

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