Image of the triangle There is a right triangle DEF with the adjacent is 12 and the acute angle of D being 25 degrees and E being the right angle... I have to figure out angle F, DF, and DE... I'm honestly not sure on what to do and i'm stressing out.. I may have worded this wrong or missed something but any help would be appreciated, thank you so much.
Solve the right triangle? Round decimals to the nearest tenth?
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0This is basic trig. Draw a picture – 2017-02-06
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0Check out my answer, if you dont understand something tell me – 2017-02-06
1 Answers
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Angle $F$. Remember, the insides of a triangle add up to $180$ degrees.
Length of $DF$. Remember, $\sin \theta=\frac{opp}{hyp}=\frac{12}{DF}$
So we have $\sin 25=\frac{12}{DF}$. You can solve from here.
Length of $DE$. After you calculate angle $F$, then we know $\tan\theta=\frac{opp}{adj}=\frac{DE}{9}$
So we have $\tan \text{ (angle F)}=\frac{DE}{9}$. You can solve from here.
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0I'm not being lazy, but i'm honestly having a hard time understanding this whole section. How do i figure out the sin 25= 12/DF? It makes no sense to me and i'm feeling stupid here. Also, the same with the length of DE. I just don't get any of this and its frustrating – 2017-02-06
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0sin $25$ you just evaluate in your calculator. We basically have $\sin(25) = \frac{12}{DF}$, and so solving for $DF$, we see that $DF=\frac{12}{\sin(25)} = 28.4$ – 2017-02-06
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0If you don't understand your textbook, I highly recommend khanacademy. – 2017-02-06
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0https://www.youtube.com/watch?v=Jsiy4TxgIME – 2017-02-06
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0is solving for DE the same as we solved for DF? – 2017-02-06
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0Yes, but in $DF$ you used $\sin$, and in $DE$, you will use $\tan$ – 2017-02-06
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0Sorry for asking a lot but.. what if i do not have a calculator? – 2017-02-06
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0Either your teacher wants you to leave it in ratio form, in which case you say $DF=\frac{12}{\sin(25)}$, or it's impossible to calculate cause its too precise. Your question says $round$, so you gotta use the calc – 2017-02-06