Tricky Geometry Help! (1 Viewer)

[gurmies]

Hey guys, this question isn't exactly Extension II maths, but I coudn't find a better place to put it, since i'm quite sure it's not 2 or 3 unit maths either. I have been stuck on this question for almost a week now...

An isosceles triangle ABC is drawn, with AB = AC, with the vertex angle 20*. From B to AC (call it E), a line is drawn, so that an angle of 20* is made with BC. A similar line is drawn from C to say, D (on AB) so that an angle of 30* is made with BC. Call the point where these two lines intersect O.

DE is connected. Now, find angle ODE and angle OED

 

[Arowana21]

doesnt make any sense, if angle BEC is also 20 degrees and becasue angle ACB and angle ABC is 80 degree becasue of the isosceles property of triangle, and also using triangle EBC u can work out that angle EBC is ALSO 80 degrees, this is screwed cos that would mean tha angle ABC is equal to angle EBC.

 

[gurmies]

Don't worry about it, there's nothing wrong with the question, but I have the solution. Probably the hardest question I have ever seen.

 

[lolman12567]

does angle OED = 30degrees and angle ODE = 20degrees?

 

[tommykins]

Can someone provide a diagram with every info on it. I cbf drawing it (can't find my bloody ruler)

 

[gurmies]

Nope the angles are not equal to that. I would draw it for you if I had some sort of non-paint oriented program =(

 

[ianc]

From B to AC (call it E), a line is drawn, so that an angle of 20* is made with BC. A similar line is drawn from C to say, D (on AB) so that an angle of 30* is made with BC

you need to specify: does BEC = 20 or BEA= 20?

same for CDA or CDB?

cheers

 

[gurmies]

Ebc = 20..

 

[youngminii]

Is angle ODE = 10 and angle OED = 30?
I'm pretty sure that's wrong 'cause when I did all my working
I made a few mistakes here and there, so half my working is incorrect, and I'm assuming you need to sub a lot of stuff into other stuff?

 

[gurmies]

Put it this way, there is very little geometry involved, all trig

 

[youngminii]

Nowai

 

[youngminii]

Hey, you never told us the answer

 

[gurmies]

answer is p long...

 

[youngminii]

Wthell
Tell us

 

[lolokay]

17'53' and 32'07'?

 

[gurmies]

lolokay, it is 17' 53", you are a complete genius. The mathematics staff at UNSW could not solve this one, except for my tutor.

 

[lyounamu]

answer is p long...

Hahahaha...that's a great call.

But you have a responsibility to post up an answer if you have got one (and if other people don't know really well).

I can see that it is related to the manipulation of the tonnes of trigonometry and algebra. But can you at least guide me to the right direction?

 

[gurmies]

ahah, sure dude..sorry if you guys thought I was being a dickhead...I really wasn't But 1: it's not my solution, it's my tutors. 2: it's actually long. Perhaps I'll scan his answer..

 

[lyounamu]

ahah, sure dude..sorry if you guys thought I was being a dickhead...I really wasn't But 1: it's not my solution, it's my tutors. 2: it's actually long. Perhaps I'll scan his answer..

Thanks.

 

[gurmies]

Damn, I can't attatch it, it's too big. What's a good picture hosting website?