Velox's Challenge Question ;) (2 Viewers)

[velox]

A chord PQ, 24cm long, is 5cm from the centre of the circle. Calculate the length of the arc PQ. I know im missing something or could be a careless error. Could someone try it? Thanks!

 

[Trebla]

This should be right, please check:

 

[Slidey]

That looks correct.

Did you get this from a 2u or a 3u book, velox? It's a 3u question (circle geo).

 

[Trebla]

That was a 3 unit question!? That was fairly easy. It should be a 2 unit question.

 

[Slidey]

Well, you must remember you are a very good mathematics student.

It is difficult for a number of reasons:
1) It's wordy
2) It doesn't lead you in
3) It requires one of the 16 circle geometry theorems
4) Upon finding the circumference of the circle, you are than required to use further trigonometry to find the final answer.

 

[dawso]

i think this chellenge question idea is becomin abit over used, lol, just keep it for the true challenging questions...

 

[velox]

lol dawso. Hence the '' Its a 2u question from fitzpatrick (chapter 17), pretty easy, however i had my calculator in gradient mode or something which threw out my trig. Thanks trebla.

 

[zahid]

That looks correct.

Did you get this from a 2u or a 3u book, velox? It's a 3u question (circle geo).

I doubt that its a 3unit question, a similar question is in the development section of the cambridge Y12 2u textbook, really does not draw on any theorems.

 

[Slidey]

It doesn't matter what part of the book it's in, it uses a 3u theorem. Yes, the theorem is intuitive but that doesn't change anything.

 

[zahid]

it uses a 3u .

I am just curious, which theorem does it use?

Because i solved it without actually being aware that I used a theorem of some sort.

 

[velox]

it came out of a 2u book, therefore it's 2u. Case closed

 

[zahid]

it came out of a 2u book, therefore it's 2u. Case closed

Thats what I had originally implied.

 

[acmilan]

"Perpendicular to chord from centre bisects chord". Whether you knew it or not, its a 3 unit theorem that many 2 unit students wouldnt know

 

[zahid]

"Perpendicular to chord from centre bisects chord". Whether you knew it or not, its a 3 unit theorem that many 2 unit students wouldnt know

ahh....yes Thankyou. I was wrong.

 

[Trebla]

"Perpendicular to chord from centre bisects chord". Whether you knew it or not, its a 3 unit theorem that many 2 unit students wouldnt know

Odd though, I learnt that theorem in Year 10 in the Mathematics Advanced core topic "Circle Geometry" at school.
Now doing Mathematics Extension 1 at school in Year 11, we haven't covered "Circle Geometry" yet, we've only covered "The Real Number System" and "Trigonometry". In tutor, where we covered the "Circle Geometry" topic, 95% of the theorems were the ones that I had already learnt in Year 10 at school.

*At my school, Mathematics Extension 1 is not separated from Mathematics 2 Unit and the course is taught as a combined course. However, Mathematics Extension 2 is separated from Mathematics Extension 1. I guess this is for the sake of conveniencing a total of five full 3 Unit classes and only one 2 unit class.

 

[Slidey]

That happened at my school, too. It changed in year 11.

Also, the year 10 topic circle geometry is an option topic, not a core; not every school covered it.

 

[Trebla]

Lol, my teacher calls them core topics. The syllabus refers to them as option topics. So...

 

[velox]

Most schools do them anyway.

 

[acmilan]

Most schools do them anyway.

I didnt....

But i guess thats because we did prelim stuff in yr 10

 

[Trebla]

But i guess thats because we did prelim stuff in yr 10

I thought you weren't allowed to learn some of the preliminary course in year 10. It's a rule that all teachers must abide by so that no one gets disadvantaged in the starting time of the preliminary course.