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Topic: mathcounts no-trig question
Replies: 7   Last Post: Jan 10, 2012 11:35 AM

 Messages: [ Previous | Next ]
 talmanl@mscd.edu Posts: 1,838 Registered: 12/6/04
Re: [MathTalk] mathcounts no-trig question
Posted: Jan 9, 2012 11:05 PM

Sin[75 Degrees] = Sin[45 Degrees + 30 Degrees].

On Jan 9, 2012, at 6:17 PM, Guy Brandenburg wrote:

>
>
> Found this question on an old Mathcounts test - a portion where calculators aren't allowed.
>
> I know the answer (3/4), which I got by using illegal methods (calculators, sines, and cosines), but I can't figure out how one could figure it out just using brain, paper, and pencil.
>
> The question poses a 75-15-90 triangle whose hypotenuse is given as the square root of three.
>
> The goal is to compute the area.
>
> Any hints or suggestions would be welcome.
>
> Guy Brandenburg, Washington, DC
> http://gfbrandenburg.wordpress.com/
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- --Lou Talman
Department of Mathematical and Computer Sciences
Metropolitan State College of Denver

<http://rowdy.mscd.edu/%7Etalmanl>
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Date Subject Author
1/9/12 Guy Brandenburg
1/9/12 RWW Taylor
1/10/12 Guy Brandenburg
1/9/12 Chris L. Yuen
1/10/12 Guy Brandenburg
1/9/12 Lars Jensen
1/9/12 Norman Wildberger
1/9/12 talmanl@mscd.edu