Trig question (1 Viewer)

[twinklegal19]

So this was the last question of a recent topic test which I'm still stuck with. Where on earth is alpha and beta anyway?

Thanks!

 

[Aysce]

I'm pretty sure angle OAG is beta whilst angle AOG is alpha.

 

[RivalryofTroll]

I'm pretty sure angle OAG is beta whilst angle AOG is alpha.

wait isn't it alpha = ACG?

wait, nvm..

 

[twinklegal19]

I'm pretty sure angle OAG is beta whilst angle AOG is alpha.

Thanks

How can you tell though? The wording threw me off

 

[RivalryofTroll]

Thanks

How can you tell though? The wording threw me off

For Beta, AG is the vertical and AO is the line. Hence the angle formed is OAG or GAO.

 

[Aysce]

Thanks

How can you tell though? The wording threw me off

So the line AO makes an angle with the vertical ie AG so yeah - angle OAG is beta (as listed in the wording)

As for alpha, it says the vertex is at O has a semi-vertical angle alpha although im a little iffy with this part.

 

[AAEldar]

 

[pokka]

usually semi-vertical angle means half the vertex angle of the cone if you want to interpret it that way. Hint: angle AGC is alpha+beta due to sum of int. angles equalling ext. angle. I recommend that you draw the triangles AOC and AGC separately so you can find tan (alpha) and tan (alpha+beta) then work from there keeping in mind of the ratio given to you

 

[pokka]

oh darn someone beat me to it

 

[AAEldar]

That's like the 3rd time I've posted that pic here, did it for Spiral over a year ago >.< hahaha.

 

[SpiralFlex]

That's like the 3rd time I've posted that pic here, did it for Spiral over a year ago >.< hahaha.

Good times eh?

Wait I don't remember this question

 

[twinklegal19]

For Beta, AG is the vertical and AO is the line. Hence the angle formed is OAG or GAO.

So the line AO makes an angle with the vertical ie AG so yeah - angle OAG is beta (as listed in the wording)

As for alpha, it says the vertex is at O has a semi-vertical angle alpha although im a little iffy with this part.

ah thanks, I initially thought two different angles (acute/obtuse) angles can be formed from two lines intersecting, however I forgot to realise only OAG was applicable to the question lol

thank you very much I really appreciate it

usually semi-vertical angle means half the vertex angle of the cone if you want to interpret it that way. Hint: angle AGC is alpha+beta due to sum of int. angles equalling ext. angle. I recommend that you draw the triangles AOC and AGC separately so you can find tan (alpha) and tan (alpha+beta) then work from there keeping in mind of the ratio given to you

Thanks for explaining

Wasn't sure what a "semi-vertical" angle was before lol. It all makes sense now

 

[karnbmx]

no need to find angle AGO. you can find angle AGC directly from exterior angle of triangle theorem (angle OAG + angle AOG = angle AGC).