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Help with "Circles"


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Will someone help me with this IA? I can see that AO and AP' are equal because they are both radiuses of C3, but I don't understand how you can solve for OP' without a given angle! please help!

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Will someone help me with this IA? I can see that AO and AP' are equal because they are both radiuses of C3, but I don't understand how you can solve for OP' without a given angle! please help!

How much is this question worth? If it's +5 points, that probably means that you need to "think" a little harder because the question requires at least two different steps. So, maybe you need to use two different equations to find your answer :)

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Will someone help me with this IA? I can see that AO and AP' are equal because they are both radiuses of C3, but I don't understand how you can solve for OP' without a given angle! please help!

How much is this question worth? If it's +5 points, that probably means that you need to "think" a little harder because the question requires at least two different steps. So, maybe you need to use two different equations to find your answer :)

This isn't a normal maths exam question, it's part of the IA, which is composed of multiple questions. Take a look at some example IAs (I think there are some on the forum) and you'll understand that it's a whole other world.

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Will someone help me with this IA? I can see that AO and AP' are equal because they are both radiuses of C3, but I don't understand how you can solve for OP' without a given angle! please help!

sorry for the very late reply! I've been busy very lazy lately :P

okay so you know there is this AOP triangle with AOP' triangle inside, and both are isosceles triangles (AP=OP, AO=AP').

I've drawn something to guide you. look at the picture below:

BshDv.jpg

the figure on the left hand side is exactly as it is shown in the task paper, except for being rotated so that you can clearly see that it's isosceles.

when you rotate the inner triangle, you'll get the figure on the right hand side. now you see that the two triangles are actually similar. so you can work out the lengths of the triangles without having to deal with angles!

do you know what to do now?

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  • 3 weeks later...

i have a question...

i can see that triangle OAP and OAP' are both isoscles.

and if AP= OP and AO= AP'

then OA=AP'=1 because the radius for c3 is 1.

and when OP= 2, then OP=AP= 2

but then how can AP= 2, when the radius for c3 is 1?

i'm really lost :S i need help pleasseeeee!

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  • 1 month later...

Will someone help me with this IA? I can see that AO and AP' are equal because they are both radiuses of C3, but I don't understand how you can solve for OP' without a given angle! please help!

sorry for the very late reply! I've been busy very lazy lately :P

okay so you know there is this AOP triangle with AOP' triangle inside, and both are isosceles triangles (AP=OP, AO=AP').

I've drawn something to guide you. look at the picture below:

BshDv.jpg

the figure on the left hand side is exactly as it is shown in the task paper, except for being rotated so that you can clearly see that it's isosceles.

when you rotate the inner triangle, you'll get the figure on the right hand side. now you see that the two triangles are actually similar. so you can work out the lengths of the triangles without having to deal with angles!

do you know what to do now?

but I still need to know the angle in order to get the length of OP' right? or issit just based on ratios?

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  • 2 months later...

Will someone help me with this IA? I can see that AO and AP' are equal because they are both radiuses of C3, but I don't understand how you can solve for OP' without a given angle! please help!

I have just been given this IA, was wondering if there are any useful points that you could help out with since you have already gone through it :)!!!!

pleeeaaasseeeee? :D

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I'm pretty sure I've written all the necessary clues in post #7. can you just read them first? if you have, read again every single word and try to understand it. if you only skim through you will never understand anything.

then if you have other questions you can just post it here. but please be specific! I can't be explaining the whole thing again. tell me which part you don't understand and then I'll explain it to you.

Edited by Desy Glau
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  • 2 weeks later...

I was thinking of using similar triagles as well, but the first task clearly states to "Use a trigonometric approach to find OP', when OP=2, OP=3, and OP=4". If similar triangles don't fall under trigonometry then I won't be able to use such an approach for this task right?

Edit: Or do similar triangles DO fall under trigonometry? I always thought trigonometry meant using sin, cos, tan, etc.

Edited by illCyz
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ooh.. really... it seems like we received different task sheets... because mine didn't mention using trigonometric approaches anywhere

I was thinking of using similar triagles as well, but the first task clearly states to "Use a trigonometric approach to find OP', when OP=2, OP=3, and OP=4". If similar triangles don't fall under trigonometry then I won't be able to use such an approach for this task right?

Edit: Or do similar triangles DO fall under trigonometry? I always thought trigonometry meant using sin, cos, tan, etc.

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