Circle geometry (1 Viewer)

[Just.Snaz]

I hope it BURNNSSSSSS

But, unfortunately, it'll be sitting there, staring wide-circled at me on monday morning.. so I was hoping someone could supply me with a bit of expert advice on how I could possibly come CLOSE to the answer..

From my teacher I've heard, "try work backwords" and my tutor says "state whatever you see and they'll give you the marks even if you can't/don't make the connection" but is there anything else? Maybe some sort of "correct way of thinking"? Does practise really make perfect in this case?

Thanks guys..

 

[tacogym27101990]

i write down everything i can see from the diagram
and then usually i find that ive solved it thru that
i also try to solve it in my reading ttime

 

[midifile]

I hate circle geometry so much - 3 unit is bad enough, 4 unit is just hell. When I do questions I think in my head what rules apply to what you are trying to find/prove. So if it is an angle subtended at the circumference I try and find any other aginles subtended from the arc, cyclic quadrilaterals, alternate angle theory, angles at centres etc and see if any of those things help in working out the angle.

 

[Undermyskin]

What? I absolutely love it!

Yes you have to write it 'backwards'.

Let's say you want to prove AB=AC <-- two equal triangles <-- SAS <-- 1. two similar triangles 2. two sides of a square. etc. This is just an example of how to make up a "flow chart".

Hey, circle geometry is tricky but pretty awesome! Com'on, it's much better conics which is, honestly, so tedious!

 

[Just.Snaz]

Thanks guys I'll keep what you said in mind.

I've already however have been writing everything I see and working it out in reading time and the whole 'flow chart' thing is a cool way but yeah, I was hoping there was some sort of, maybe 'trend' I could look out for.

Like, for eg, in 3 unit, you nearly always need to prove a cyclic quad and the answer might as well slap you in the face, but for 4 Unit, its just new concepts all over the place..

Hey, circle geometry is tricky but pretty awesome! Com'on, it's much better conics which is, honestly, so tedious!

Conics is the BEST <3

 

[midifile]

Thanks guys I'll keep what you said in mind.

I've already however have been writing everything I see and working it out in reading time and the whole 'flow chart' thing is a cool way but yeah, I was hoping there was some sort of, maybe 'trend' I could look out for.

Like, for eg, in 3 unit, you nearly always need to prove a cyclic quad and the answer might as well slap you in the face, but for 4 Unit, its just new concepts all over the place..



Conics is the BEST <3

Yea. Id chose conics any da over circle geometry.

My maths teacher said 4 unit questions often (not always) contain similar triangles, but they are less obvious and harder to find, and unlike 3 unit where they will first tell you to prove that two triangles are similar and then find angles or whatever, they wont tell you so you will have to recognise it on your own.

 

[Aplus]

Circle Geometry is just problem solving and thinking effectively.

 

[conics2008]

hey dont forget to use radius, it sometimes really helps you =] i remember 3unti circle, i aced it.. cant wait for 4unit circles, because im starting to forget it.

before you attempt the quesiton, mark on all the properties on the question and then attempt the question..

this is just my method.. use radius and tangents dont forget them.. they can become very very useful =}

 

[nick90]

yeah, as others have suggested, i reckon that solving the problem on the diagram before you start writing anything down is a must-do if you want your final solution to make sense. the converse theorems seem to come up a fair bit in 4u exams, so making sure you know them well would be useful.

By the converse theorems, I mean:
- the circle whose diameter is the hypotenuse of a right-angled triangle passes through the third vertex.
- if an interval AB subtends the same angle at two points P and Q on the same side of AB, then the four points A, B, p and Q are concyclic.
- if a pair of opposite angles of a quadrilateral are supplementary (or if an exterior angle of a quadrilateral equals the interior opposite angle), then the quadrilateral is cyclic.

Using past HSC and trial questions as a guide for circle geom questions is a good idea too imo. Sometimes they have a bit of a different 'feel' from textbook questions.

Hope you find something i said useful