cerbera
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| posted on 31/10/13 at 12:20 PM |
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Calling Maths Gurus
My daughter is going to sit the American SAT examine and is doing a bit of study in preperation for this. We've come across a maths question
that has stumped both of us, not that we're maths genii, so I'm hoping someone knows the answer but more importantly can explain why.
Cheers
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ed1801
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| posted on 31/10/13 at 12:28 PM |
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This should help, and has the explanation.
http://www.mathopenref.com/chord.html
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dave_424
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| posted on 31/10/13 at 12:38 PM |
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quote:
Originally posted by ed1801
This should help, and has the explanation.
http://www.mathopenref.com/chord.html
Isn't it asking for the arc length?
Chord length is 2r*sin(c/2)
r = 5
c = 148 degrees
chord length = 9.61261
Arc length = diameter*pi*(angle/360)
= 10*pi*(148/360)
= 12.91544
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dave_424
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| posted on 31/10/13 at 12:41 PM |
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Looking again, can you list the possible answers and the angle, I thought it was 16 degrees but is unclear
Dave
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cerbera
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| posted on 31/10/13 at 12:47 PM |
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Sorry for the bad picture.
The angle is 36
the posible answers are...
A) PI / 2
B) PI
C) 3PI / 2
D) 3PI
E) 7PI / 2
and yes, it's asking for the arc length.
[Edited on 31/10/13 by cerbera]
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cerbera
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| posted on 31/10/13 at 12:53 PM |
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The more I look at this the more I think that the possible answers are wrong.
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dave_424
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| posted on 31/10/13 at 12:53 PM |
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Angle is 180-36-36 which gives you the angle at O = 108 degrees
Arc length = diameter*pi*(angle/360) = 10*pi*(108/360)
=9.42477....
divide by pi gives you 3
Answer = 3pi
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matt_claydon
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| posted on 31/10/13 at 12:58 PM |
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Angle ODB = 36 degrees, that makes angle BOD = 180-36-36 = 108 degrees.
360/108 = 3 1/3
a full circumference is d * pi = 10pi
10pi / (3 1/3) = 3pi
Edit: too slow!
[Edited on 31/10/13 by matt_claydon]
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cerbera
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| posted on 31/10/13 at 01:00 PM |
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Ta very much.
Will be able to sleep tonight now 
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Norfolkluegojnr
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| posted on 31/10/13 at 04:47 PM |
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I should have paid more attention in maths. i have no idea what you lot are talking about.
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jacko
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| posted on 31/10/13 at 05:16 PM |
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quote:
Originally posted by Norfolkluegojnr
I should have paid more attention in maths. i have no idea what you lot are talking about.
You didn't need too just ask this lot on locost 
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JC
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| posted on 31/10/13 at 07:22 PM |
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[img]
 
3 pi
[/img]
My kind of answer
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cerbera
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| posted on 31/10/13 at 07:58 PM |
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quote:
Originally posted by JC
[img]
3 pi
[/img]
My kind of answer
ROFL
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Alan B
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| posted on 2/11/13 at 07:37 PM |
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How come someone from Preston (like I am) has a child taking US SAT exams (like I had)...?
Alan
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T66
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| posted on 2/11/13 at 08:09 PM |
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Ask me the time......
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cerbera
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| posted on 2/11/13 at 08:52 PM |
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quote:
Originally posted by Alan B
How come someone from Preston (like I am) has a child taking US SAT exams (like I had)...?
Alan
Because she's looking to go to america on a football scholarship 
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Alan B
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| posted on 2/11/13 at 11:07 PM |
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Best of luck to her, she'll enjoy it.
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Macbeast
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| posted on 3/11/13 at 07:29 AM |
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You're engineers fgs !
Get a piece of string and measure it.
I'm addicted to brake fluid, but I can stop anytime.
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