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Help with "Circles"


JIB

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I still don't understand how to find the angles of the triangle AOP'. Can someone please help me? :( I figured out angle O, but now I'm stuck trying to find angle P'

If you're using non right-angled trig, you'll need to make use of another rule (used in nra trig) besides the cosine rule to work out P'. That's the best I can do without directly stating what you need to use!

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I'm completely stumped on the limitations. I have one limitation, involving what happens when r is double or more OP - there's no triangle, just a straight line, though OP' can still be calculated correctly by my general statement in this situation so I'm unsure if it's a true limitation...but it's the best I've got. Can anybody point me in the right direction?

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For the first part I got the General statement: OP' = r/OP

For the SECOND part this is what I got..... Tell me if I'm wrong or if you got different answers.... cuz idk what the general statement is from this...?? how do I find it?

when OP=2.....

r=2

A and O =60.0

P=60

a or OP'= 2

r=3

A and O = 41.4

P=97.2

a or OP'= 4.5

this one I don't understand either...

r=4

A and O = 0

P=180? etc.....????

Edited by travisjames95
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  • 2 weeks later...

I still don't understand how to find the angles of the triangle AOP'. Can someone please help me? :( I figured out angle O, but now I'm stuck trying to find angle P'

If you're using non right-angled trig, you'll need to make use of another rule (used in nra trig) besides the cosine rule to work out P'. That's the best I can do without directly stating what you need to use!

You actually don't need to use another rule other than the cosine rule. Well I didn't :P. But you have to look at the different triangles you have and how they relate so that you can find the angle P'

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Description level 5 (max) in Criterion C is "The student tests the validity of the general statement by considering further examples".

What exactly are 'further examples' in this case? Is it just that you solve this with similarities and trigonometric approach or is it something else? Could somebody direct me, if it's something else?

I think that they want you to just take different values of OP and r and see how it affects OP'. In the question it says "Use technology to investigate other values of r and OP." So you can do so using whatever program/software you have been using.

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can somebody tell me how to do the technology and op' general statement part?

I found the general statement for the first two parts but how do you go about the technology part? I know we have to use geogebra, atleast im using that, but what after that? Im stuck :|

How is it different from the first two? cause even then we found the general statement for OP'.

Nevermind that, it was just me being stupid :P

Edited by aweffingsome
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Listen, no we never assume they are parallel, why would you say such a thing! listen, we know that AO and AP' are always equal since they are the radii of Circle (C3), using cosine rule we can find angle AOP' , since triangle AOP' is an isosceles triangle then angle AOP' is equal to angle AP'O. Using this fact we find angle OAP' , then we use angle OAP' to find the length of the side OP'!! its really simplw once you get it man! try sketching with a pencil or I advice you to use GeoGebra! (AWESOME software)

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