Question

How to show angle A = 1/2 angle O ?
Please, help

Answer 1

So we have an inscribed angle,
and a central angle.

There must be some simple geometric way to show it.. hmmm thinking

Answer 2

Hmm when I remember this was from basic angles in a circle : CAB is an inscribed angle so <BAC = 1/2 arc(BC) and <COB is a central angle meaning <COB = arc(CB). So you get <BAC = 1/2 <COB. Unless you're trying to prove the formulas.

Answer 3

proof

Answer 4

bust out Euclid's Elements

Answer 5

@math&ing001 Yes, I am. I have to prove the theorem. I know how to prove it if the center is inside the inscribe angle.

Answer 6

I see, ok let me think about it

Answer 7

Do you want to see the proof of this part? it may ring some bells, I think

Answer 8

OK sure =)