Difference between revisions of "Ptolemy's Theorem"

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[[File:Ptolemy's_Theorem.png]]
 
[[File:Ptolemy's_Theorem.png]]
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The key construction step is (b), which allows us to form 2 pairs of similar triangles:
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Examining the similar triangles in (c), we have <math>\frac{j}{d} = \frac{b}{p}</math>, so <math>jp = bd</math>
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Examining the similar triangles in (d), we have <math>\frac{j}{c} = \frac{a}{q}</math>, so <math>jq = ac</math>
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So <math>j(p+q) = bd + ac</math> ... Q.E.D.
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This theorem rests upon:
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[[File:InscribedAngle.gif]]

Latest revision as of 16:42, 14 January 2016

Ptolemy's Theorem.png

The key construction step is (b), which allows us to form 2 pairs of similar triangles:

Examining the similar triangles in (c), we have {\frac  {j}{d}}={\frac  {b}{p}}, so jp=bd

Examining the similar triangles in (d), we have {\frac  {j}{c}}={\frac  {a}{q}}, so jq=ac

So j(p+q)=bd+ac ... Q.E.D.

This theorem rests upon:

InscribedAngle.gif