Posted: 2/10/2008 9:32:19 PM EDT
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My brain is just too foggy tonight. I still remember calculus, but don't remember the answer to this basic question. Please help me out and if I'm in a good mood, I might send you a cookie. Assume you have a right triangle: |\ |..\ |....\ |......\ |........\ |.........\ |..........\ |...........\ |............\ |..............\ ___________ <--- known angle base You know the following facts: 1. This is a right triangle (despite my crapy ascii drawing) 2. The known angle is 35 degrees (or anything else you want) 3. The base length is known (let's say it's 2, 3, 4, whatever). Question: What are the lengths of the left side and hypotenuse? I'm pretty sure it's something to do with the sine, cosine, April Levine - something like that. Can anybody help me out? Edited because all my spaces disappeared when building my triangle. |
| I've forgotten all the trig I knew, but you don't need trig to figure that out. You can calculate the length of the unknown sides by using the ratio of the known side to its angle. I was going to figure it out, but my spreadsheet crashed and I don't want to reboot now. Incidentally, the triangle is drawn incorrectly; the shortest side is opposite the 35 deg. angle. |
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You would need to use the law of cosines on this one. The side opposite of the known angle is called the opposite side and the other is the adjacent side. You might be able to use the sine rule on this too Wiki has some good articles on these rules. I like the sine rule as it is simple and easy to remember. |
Hooray for you. You added to your post count, but didn't add any value. None of the above information you provided was unknown, so why did you post? |
However, what he is asking is usually taught in trigonometry class in high schools. You have two angles (actually, as you point out , all three - but for this, the third is irrelevent) plus a known length between them. Angle-side-angle. Law of |
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I just finished helping tutor my son on this stuff a couple hours ago before coming into work!!! There's the SOHCAHTOA for figuring the lengths given an angle and at least one of the side lengths . Then there are some special rules when it's a 30-60-90 triangle :Hypotenuse is double the length of the short side and the long side is the short side multiplied by the square root of 3; and in a 45-45-90 triangle: Hypotenuse length is the side length multiplied by the square root of 2. Damn, it's like going thru high school all over again!!! |
Yep. I can usually count on Arfcom to come through with an actually useful response to go along with the 15-20 fluff, irrelevant and post-whoring responses. |