Dravin Posted March 9, 2011 Report Posted March 9, 2011 The Problem:A plane leaves airport A and travels 560 mi to airport B at a bearing of N32°E. The plane leaves airport B and travels to airport C 320 mi away at a bearing of S72E. Find the distance from airport A to airport C.Okay, this in my mind gives me a set up of:Now that gives us:c = 560, a = 320Now to get B, I had to draw a picture to visualize:The red section of the angle in Q3 is the direction the plane was heading from (and Q1 is if it didn't stop N32E). The blue line is the direction the plan is going in Q4 S72E and Q2 if it was flying in reverse. Anyway between the lines in Q3 and Q4 is (360-72)-(180+32) = 76°.So using the law of cosines I should be able to:b^2 = 560^2 + 320^2 - 2*560*320*cos(76°) = ~318457Root things and we get b = ~574The book is saying the answer is ~710I'm sure I'm making a really stupid error that will result in a facepalm when someone points it out to me. Quote
lizzy16 Posted March 9, 2011 Report Posted March 9, 2011 I have no idea..but do you (or anyone else) have any knowledge of logs? and log functions? for my High School trig class? Quote
Guest Posted March 9, 2011 Report Posted March 9, 2011 (edited) You got your NE angle coming off the horizontal line instead of the vertical line.Here ya go:P.S. A and B are actually the angle on the horizontal line... not the middle part... bad drawing. C is the angle we're trying to find, so it shouldn't matter where A and B are because we have the lengths of both sides. Edited March 9, 2011 by anatess Quote
slamjet Posted March 9, 2011 Report Posted March 9, 2011 You got your NE angle coming off the horizontal line instead of the vertical line.Here ya go:Are you KIDDING ME!!!!! Quote
Guest Posted March 9, 2011 Report Posted March 9, 2011 Are you KIDDING ME!!!!!Didn't I tell you, you don't know what you're missing? GEEK MANIA, MAN!:D:D Quote
slamjet Posted March 9, 2011 Report Posted March 9, 2011 Didn't I tell you, you don't know what you're missing? GEEK MANIA, MAN!:D:DSo what was that about your cousins? Quote
Guest Posted March 9, 2011 Report Posted March 9, 2011 So what was that about your cousins?I got a ton of them... super pretty... card-carrying members of the geek club............ and they need visas.:D:D Quote
slamjet Posted March 9, 2011 Report Posted March 9, 2011 I got a ton of them... super pretty... card-carrying members of the geek club............ and they need visas.:D:DFor the second time tonight, I've got nothing Quote
classylady Posted March 9, 2011 Report Posted March 9, 2011 Wow, Anatess! I'm impressed! How come I can't remember any of this from my college Trig, Calculus, or Physics? Probably because I don't want to remember! Thank heavens I finished my math courses. Quote
Dravin Posted March 9, 2011 Author Report Posted March 9, 2011 (edited) You got your NE angle coming off the horizontal line instead of the vertical line..Okay, that makes sense. At least it looks like, baring the bearing snafu*, that my thought process is the right idea. Thank you.* You'd think being in an oceanography lab I'd grok that, but I swear it was taught a 360 degree bearing not degrees NW/NE/SW/NE off North/South. I blame that up to this point, everything I've dealt with in trig (reference angles, standard position and the like) works off the X-axis not the Y-axis as a reference. Edited March 9, 2011 by Dravin Quote
Guest Posted March 9, 2011 Report Posted March 9, 2011 Okay, that makes sense. At least it looks like, baring the bearing snafu*, that my thought process is the right idea. Thank you.* You'd think being in an oceanography lab I'd grok that, but I swear it was taught a 360 degree bearing not degrees NW/NE/SW/NE off North/South. I blame that up to this point, everything I've dealt with in trig (reference angles, standard position and the like) works off the X-axis not the Y-axis as a reference.For the NE/NW/SW/SE stuff... I basically head the direction of the first letter, then move to the second letter at the angle provided. So that, NE would be... from the point of reference, I go North (vertical line up), then veer East by 32 degrees and then SE would be... from the point of reference, head South (vertical line down), then veer East by 72 degrees...Oh, I just noticed I put 72 on that NE angle instead of 32... another typo. But, you see the 58 there, so you know it should have been 32. Hey, I did it in a hurry! Wow, Anatess! I'm impressed! How come I can't remember any of this from my college Trig, Calculus, or Physics? Probably because I don't want to remember! Thank heavens I finished my math courses.I had a really good teacher classy... Okay, so this is the teacher I was telling you guys about in another thread who flunked his own son 3 times... but still, he was a really good teacher. Quote
Wingnut Posted March 9, 2011 Report Posted March 9, 2011 I got a ton of them... super pretty... card-carrying members of the geek club............ and they need visas.:D:DDesperately. Seeking. Laugh. Button.No kidding. Quote
pam Posted March 9, 2011 Report Posted March 9, 2011 At least it looks like, baring the bearing snafu*, I can't believe you used that term on an lds site..and a moderator no less. Quote
Jennarator Posted March 9, 2011 Report Posted March 9, 2011 Wow.....no clue what even going on......Math hurts my brain! Quote
pam Posted March 9, 2011 Report Posted March 9, 2011 I just had to read the title of the thread and that had my brain screaming in pain. Quote
Just_A_Guy Posted March 9, 2011 Report Posted March 9, 2011 Okay, that makes sense. At least it looks like, baring the bearing snafu*, that my thought process is the right idea. Thank you.* You'd think being in an oceanography lab I'd grok that, but I swear it was taught a 360 degree bearing not degrees NW/NE/SW/NE off North/South.Didn't the Navy quit using that notation back around World War 1? Quote
pam Posted March 9, 2011 Report Posted March 9, 2011 Didn't the Navy quit using that notation back around World War 1? They were still using it when I worked for the Navy. And no that was NOT during WWI contrary to what many on this site believe. Quote
Just_A_Guy Posted March 9, 2011 Report Posted March 9, 2011 Yeah, we know. You must have some great stories about serving with John Paul Jones, though. Quote
slamjet Posted March 9, 2011 Report Posted March 9, 2011 They were still using it when I worked for the Navy. And no that was NOT during WWI contrary to what many on this site believe. Those silly people, We all know it was on a Roman galley ship Quote
rameumptom Posted March 9, 2011 Report Posted March 9, 2011 For Dravin, Trigonometry help. For everyone else, there's GPS and Google.... Quote
Wingnut Posted March 9, 2011 Report Posted March 9, 2011 They were still using it when I worked for the Navy. And no that was NOT during WWI contrary to what many on this site believe. Okay, well, I was going to make a Civil War joke, but I see that even worse has already been done. Pam, I gotta say -- you walked right into that one. :) Quote
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