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bonanova

Question

Triangle ABC is isosceles.

Find angle x.

post-1048-1221180554_thumbgif

Do not assume the figure is drawn to scale.

Do not use the law of sines.

Use simple geometric reasoning, like


  • Isosceles triangles have two equal angles and sides.
  • The angles of a triangle sum to 180 degrees.
  • Things like that.

Have fun.

You can add a line or two if you think it will help.

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ADEB is not a trapezoid.

oops you're right...quadrilateral ADEB

it's been way too long since i was in geometry...

Edited by Impervious

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What is angle BED and how did you get you come by the number?

I meant BEA again with the chicken scratch haha

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What is angle BED and how did you get you come by the number?

i have BED as 60.

BE_ = to 30 and BDE = 100

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How did you find angel BED???

If anyone finds angle BED you've solved the puzzle, since x=BED-30

If you did get angle BED, could you please explain how???

You could also solve the puzzle if you find angle BDE, having x=130-BDE

Anyone has another hint???

Edited by JarZe

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How did you find angel BED???

If anyone finds angle BED you've solved the puzzle, since x=130-BED

If you did get angle BED, could you please explain how???

raven got it first, and after using my method of getting all other angles available i decided to solve for ADEB and sort of cheated after knowing what total number each triangle needed to add up to 180° i just plugged sets of number that I wrote out that would total the needed numbers

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raven got it first, and after using my method of getting all other angles available i decided to solve for ADEB and sort of cheated after knowing what total number each triangle needed to add up to 180° i just plugged sets of number that I wrote out that would total the needed numbers

Can you post the angles you have...

I edited my previous post since I wrote the wrong formula and angles...

But I'm left with some angles that I don't know how to find, which are BED, BDE... You could also solve it from the upper part needing angles CDE or CED...

Still don't know how to find these...

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How did you find angel BED???

If anyone finds angle BED you've solved the puzzle, since x=BED-30

If you did get angle BED, could you please explain how???

You could also solve the puzzle if you find angle BDE, having x=130-BDE

Anyone has another hint???

you dont find it like that

you have to find what angle CDE is to solve this.

I am posting a full solution as soon as i type it all up. (edit: and remember exactly each step to it so you can follow along) you see i am at work and keep getting interrupted lol...

Edited by solemnraven

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Can you post the angles you have...

I edited my previous post since I wrote the wrong formula and angles...

But I'm left with some angles that I don't know how to find, which are BED, BDE... You could also solve it from the upper part needing angles CDE or CED...

Still don't know how to find these...

I'm gonna let solemnraven do it since it was after all her solution :)

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I'm gonna let solemnraven do it since it was after all her solution :)

hey if you can do it faster than me, by all means go for it.

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hey if you can do it faster than me, by all means go for it.

Oh no be my guest, i should be working instead of being on here, but you all are much more interesting and entertaining. :)

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no my answer is wrong....

go back to solving this cause i lost it trying to recreate my steps :lol:

fail

Nope you were right and I was wrong, I just replugged in your numbers :)

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Nope you were right and I was wrong, I just replugged in your numbers :)

I hate to break it to you guys,

20 deg.

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So I was working away on this and had pretty much given up. I had gotten to the point where there were only a couple of angles left to figure out (of course, x being one of them) when I realized I had made a mistake steps and steps earlier.

UGH!

Back to the drawing board!!! :rolleyes:

PS - Can't wait for simple geometry problem 2!

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I hate to break it to you guys,

20 deg.

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

ok I'm better now :D

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AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

ok I'm better now :D

yeah no im not

im redrawing this over and over and i have such a migraine.

i was so sure it was right, but then i couldnt recreate it

post the full solution please before i hurt one of my co-workers :D

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yeah no im not

im redrawing this over and over and i have such a migraine.

i was so sure it was right, but then i couldnt recreate it

post the full solution please before i hurt one of my co-workers :D

Yeah d3k3....post your solution....Me and raven my going on a rampant office homice...two different offices same reason, different states....that would make the news...hmm the BD would be famous.....maybe you shouldn't post it. :P

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Yeah d3k3....post your solution....Me and raven my going on a rampant office homice...two different offices same reason, different states....that would make the news...hmm the BD would be famous.....maybe you shouldn't post it. :P

uh oh

strangely enough i see another murder mystery post involving us as the killers on BD

(wait...i just gave away the answer didnt i)

whoops!

:P

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one more reply before i leave work

what i have been trying to do now is use algebra, where x+y (where y= angle ED_)=130

but i need another formula.

edit: clarification

Edited by solemnraven

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Just to stop the pain in my head, I plugged this geometry into AutoCAD, and the answer is definitely 20 degrees. But for the life of me, I can't find the answer without using sine/cosine or some other method.

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