- #1
Buri
- 273
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Well this isn't a homework question (I'm just trying to refresh my memory from the plane geometry I did in high school) and so, I was reading through cyclic quadrilaterals on wikipedia and I don't see how certain angles are equal. Here are two images taken from wikipedia:
http://upload.wikimedia.org/wikipedia/commons/d/d1/Ptolemy's_theorem.svg
http://upload.wikimedia.org/wikipedia/en/8/8b/Ptolemy_sine_proof.svg
How are the blue angles equal? Or the theta 2 equal?
I've tried writing things in different way and extending lines, but to no avail. Any help?
http://upload.wikimedia.org/wikipedia/commons/d/d1/Ptolemy's_theorem.svg
http://upload.wikimedia.org/wikipedia/en/8/8b/Ptolemy_sine_proof.svg
How are the blue angles equal? Or the theta 2 equal?
I've tried writing things in different way and extending lines, but to no avail. Any help?