Dat circle geo (3 Viewers)

[fishrushed]

Apparently some of my friends said it was easy, saying it was "textbook stuff". I felt really smart after doing the question probably because I've never done much questions where you had to construct something that was not hinted at in the question.

 

[spongebob1]

I did a kite of BQAP with Q(T)P being the cross section of it proving opposite sides were equal. would this be valid or no?

 

[spongebob1]

shouldve done similar triangles though...

 

[MATHmaster]

How many marks will I lose if I assume it's a straight line?
I used alternate angles for angle qbt and angle pat and the other two, then 'proved' it was collinear. Can I get 2/3?

 

[Web Addict]

I constructed the common tangent at T and proved that the angles were vertically opposite, therefore Q, T and P are colliear. I wonder if this would be accepted.

 

[SpiralFlex]

This goes to show you should always look at the wording first as well as the diagram.

 

[bangladesh]

I did that whilst knowing it was wrong coz I had no other method of doing it lol

+1

 

[Plaguesbread]

How many marks were given if you prove that the triangles are similar?

 

[RealiseNothing]

How many marks were given if you prove that the triangles are similar?

How did you do that?

 

[yasminee96]

I don't understand why it can't be assumed as a straight line? It says "the line AT intersects C2 at B", so doesnt it just suggest that the line AT is produced to B?

 

[RealiseNothing]

I don't understand why it can't be assumed as a straight line? It says "the line AT intersects C2 at B", so doesnt it just suggest that the line AT is produced to B?

That's all good. But if you use alternate angles on angle BQP and APQ, that's assuming that QTP is a straight line in the first place.

 

[SpiralFlex]

I don't understand why it can't be assumed as a straight line? It says "the line AT intersects C2 at B", so doesnt it just suggest that the line AT is produced to B?

I'm gonna say it's a poor choice of wording. Well at least to me it sounds ambiguous. The sentence quoted makes no sense to me. Or maybe my English isn't up to scatch

 

[yasminee96]

That's all good. But if you use alternate angles on angle BQP and APQ, that's assuming that QTP is a straight line in the first place.

Ahh, yes, QTP cannot be assumed as a straight line. Fair enough then

 

[bangladesh]

How did you do that?

All angles are equal?
That's what i used to prove...

 

[RealiseNothing]

All angles are equal?
That's what i used to prove...

But how did you prove that?

 

[AnimeX]

oh crap >.>

 

[MisterHewson]

You cannot assume QTP is a straight line, hence you cannot say <BQT = <TPA

 

[bangladesh]

But how did you prove that?

It was the only way i could think of, BUT
You say that they are similar, then you say that the triangles touch at T and you use the other line to prove that the points were collinear. I can't remember the points exactly because i have forgotten if it was A,B,C or whatever it was.
Not sure if it's the right way tho, but it was the only way that i thought of.

 

[RealiseNothing]

It was the only way i could think of, BUT
You say that they are similar, then you say that the triangles touch at T and you use the other line to prove that the points were collinear. I can't remember the points exactly because i have forgotten if it was A,B,C or whatever it was.
Not sure if it's the right way tho, but it was the only way that i thought of.

But how are they similar? You would have to assume the result to prove it (unless there is some really obscure way of doing so).

 

[iBibah]

This is how I did it, which I'm pretty sure is right: