Im watching one of khan's videos:(adsbygoogle = window.adsbygoogle || []).push({});

http://www.youtube.com/watch?v=Qwet4cIpnCM&feature=player_embedded#at=468

And he's using the pythagorean theorem to solve height of a 30-60-90 triangle.

Prior to everything, I think I have a good understanding on how it all works, however, I still don't feel like I understand it fully.

From what I understand, pythagorean theorem's formula is: base^(2) x height^(2) = hypotenuse^(2).

Now if you watch the video and skip to the 8:00 mark, everything seems to make sense to me except the part where he adds '4' as the denominator under h^(2), nor do I understand how he got 'A=h^(2)(1 - 1/4).

Where did the 4 come from?

Sorry if this is an obvious question, Im self teaching and really just want to learn and fully understand it.

Thanks =)

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# Question about 30:60:90 (noob)

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