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OT- Math question about a ratio from an old SAT exam

David_M

Hot Rolled
Joined
Sep 30, 2014
Location
Midway, GA, USA
Give the answer in number of turns.

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BoxcarPete

Stainless
Joined
Nov 30, 2018
Location
Michigan, USA
Is this some kind of trick question? If there were a "4" as a choice I'd consider it because it goes around the circle for another "turn" but it's just 3 otherwise.
 

plastikdreams

Diamond
Joined
May 31, 2011
Location
upstate nj
It's nine...if you divide 3 by 1 you get three, then multiply 3 by the answer and you get 9...nine divided by .33 (1/3) is 27.27...the square root of 27.27 is 5.222 multiply that by pi and get 16.405...tan(16.405) is .29, round up to .3 and multiply by 30 and bam 9.
 

Demon69

Titanium
Joined
Mar 3, 2013
Location
Area 69.
Thats interesting. In a sense its a matter of where circle A is viewed from. Ie looking out from the centre of circle B or directly down over circle A.
Either way I blame Boozy D :D
 

plastikdreams

Diamond
Joined
May 31, 2011
Location
upstate nj
Thats interesting. In a sense its a matter of where circle A is viewed from. Ie looking out from the centre of circle B or directly down over circle A.
Either way I blame Boozy D :D

You have to look at the circles not as circles but as lines bent into a circle...but not any circle, a perfect circle with no chords or defects. It's an object of such perfection that no other 2 circles are as perfect...nor will there ever be.
 

Demon69

Titanium
Joined
Mar 3, 2013
Location
Area 69.
You have to look at the circles not as circles but as lines bent into a circle...but not any circle, a perfect circle with no chords or defects. It's an object of such perfection that no other 2 circles are as perfect...nor will there ever be.
And the Lord said "let there be lulz," and there was lulz.
 

beege

Stainless
Joined
May 18, 2007
Location
Massachusetts
So here's the logic I find in this If I were to roll the smaller circle on a line three times the length of the circumference of the smaller circle, the center of the circle travels the same length as the line. Three rotations. Now if I make the line into a circle, the center of the circle will travel 1 + 1/3 the circumference of the large circle, or 4/3. It's all about how far the center travels. 4 rotations.
 

EPAIII

Diamond
Joined
Nov 23, 2003
Location
Beaumont, TX, USA
"OK, Lucy; you have some splaining to do."

This is not the first or only time the people who wrote those exams got it wrong. I can recall a number of times where I had to stop and think, now what were they thinking, in order to bet the desired answer and a better grade.



It's nine...if you divide 3 by 1 you get three, then multiply 3 by the answer and you get 9...nine divided by .33 (1/3) is 27.27...the square root of 27.27 is 5.222 multiply that by pi and get 16.405...tan(16.405) is .29, round up to .3 and multiply by 30 and bam 9.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
Roll the big circle out flat, it's a rack and the small one a pinion. Length of rack is 3 times the circumference of the pinion.
 








 
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