I'm looking for a proof of a sine rule without using algebra at all.
There are many proofs which uses geometric approach on the beginning but at the end there is always something like:
"now multiply both sides by x" or
"solve for h and that gives you something".
I'm looking for something which is based only on length, area and maybe proportion...
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Ok. I've got it. Answers given by Brian Tung and Mark Bennet are fine, I can agree that they are kind of "purely geometric", but what I meant is something like that:
It's still difficult to explain what I'm really asking for, but my intuition is that it's easier to understand geometric proof when I deal with length and area using algebra only if necessary.