


Home  Sitemap  Book Tour  Astrology  Astronomy  Mythology  Order  Sample Readings  Testimonials  About Carl  Contact 
The proposition now bearing Pythagoras' name was discovered on a Babylonian tablet (c. 19001600 BC) written more than one thousand years before Pythagoras' time. In addition, Pythagoras was captured by the Persians and taken captive to Babylon in 525 BC, where he spent five years before miraculously escaping to Samos. Pythagoras, however, is the first credited with actually having proved it using the deductive proof sequence of geometry. The Pythagorean Theorem states that a square drawn on hypotenuse (the longest side) of a right triangle is equal in area to the sum of the squares drawn on the other two sides (the legs). This is shown both geometrically and algebraically (c^{2} = a^{2} + b^{2}) in the figure above. One of many proofs follows below: 
Statement 
Reason 
1. draw lines segments BF and AK  1. two points determine a unique line 
2. through C construct CL ║to BD intersecting AB at M  2. thru an external pt. there is 1 parallel 
3. angle BAC = angle BAC  3. selfidentity 
4. angle FAC = angle BAE  4. all right angles are = 
5. angle FAC + angle CAB = angle CAB + angle BAE  5. if =s are added to =s, the sums are = 
6. ΔABF = ΔAEC  6. SAS (congruence by sideangleside) 
7. area ΔABF with altitude AC on base AF =˝ area □ACGF  7. area Δ = ˝ area □ same base & alt. 
8. area ΔAEC with altitude AM on base AE = ˝ □area AELM  8. area Δ = ˝ area □ same base & alt. 
9. ˝ area □ACGF = ˝ area □AELM  9. transitive property of = 
10. area □ACGF = area □AELM  10. if =s multiplied by =s, products are = 
11. similarly area □BCHK = area □BDLM  11. counterparts of reasons 3.  10. 
12. but area □AELM + area □BDLM = area □ABDE  12. the whole = the sum of its parts 
13. area □ABDE = area □ACGF + area □BCHK Q.E.D.  13. =s may be substituted for =s 
This proof is probably the most famous of the many known proofs of the Pythagorean Theorem, the figure above on which the proof draws being known as The Bride's Chair. This PythagorasPythagorean Theorem proof page and much of this 600page website are excerpted from the personalized Fine Art Book You and the Universe. 
Home  Sitemap  Book Tour  Astrology  Astronomy  Mythology  Order  Sample Readings  Testimonials  About Carl  Contact 
Pages 2 and 3 from your Astrology Reading in the Fine Art Book You and the Universe
Covers for the personalized
Fine Art Book
You and the Universe.
The author, his instruments, poetry, awards, reviews and horoscope charts.
© Carl Woebcke: Pythagoras: the Proof of the Pythagorean Theorem, 19912016. All rights reserved.