January 2009 SAT Math Discussion

<p>nyorker: it was def 140. the radius was 3, area of circle was 9pi, so since the area of the sector was pi, the angle of the sector was 40. the question wanted you to find the supplement of 40 iirc so 180-40=140.</p>

<p>the angle in the shaded circle thing… wasnt it 150?</p>

<p>okay ive been asking this questions for the last 15min and im getting no answers=[ so ill write in caps so maybe someone will see.</p>

<p>WAS THE ANSWER TO THE QUADRENTS (1 2 4) CHOICE C ??</p>

<p>WHAT IS THE QUESTION WHERE EVERYONES SAYING THE ANSWER IS BETWEEN 5 AND 6?</p>

<p>WHAT IS THE ANSWER TO THE TANGENT’S SLOPE (EVERYONE SAYING ITS 4/3 BUT HOW DID U GET THAT)</p>

<p>AND DID EVERYONE GET 140 FOR THE PIE THING IN THE CIRCLE?</p>

<p>Yes it was!! Didn’t the girl buy two cd’s out of six?
Since, 2(15) + 4(12) = 78</p>

<p>I put down two if I remember the answers correctly but whatever I answered it equalled to seventy-eight.</p>

<p>No, it was 140</p>

<p>ah, i see nvm yeah its 140 did the circumference =/</p>

<p>was the question with the scatterplot with the height of the trees and stuff in an experimental section?</p>

<p>scatterplot height of trees def experimental, i had no such thing</p>

<p>Number of games …………………. 12
(k-1)/k digit …………………. 8
Sequence 5, a, b …………………. 5^21
Hardcover Fiction books …………………. 4000
slope of the line tangent to the circle …………………. 4/3
Quadrants …………………. I, II, and IV
Pie chart of luxury cars …………………. the greatest number (E)
Number of CDs …………………. 2
Area increase …………………. 1% (wasn’t it decrease?!)
(x-1) (x-r) …………………. 5<r<6
Sector with area = pi …………………. 140 deg
Opposite to star …………………. blank circle</p>

<p>Experimental ? Section 4 for me</p>

<p>Set with the greatest element …………………. < 99
a question about a pentagon…and a circle trying to touch it
scatterplot…where u had to count how many trees</p>

<p>holy **** man, i got 3 easy questions wrong but got the hard ones wrong what the hell is wrong with me</p>

<p>Number of games …………………. 12
(k-1)/k digit …………………. 8
Sequence 5, a, b …………………. 5^21
Hardcover Fiction books …………………. 4000
slope of the line tangent to the circle …………………. 4/3
Quadrants …………………. I, II, and IV
Pie chart of luxury cars …………………. the greatest number (E)
Number of CDs …………………. 2
change in area of rectangle …………………. DECREASE 1%
(x-1) (x-r) …………………. 5<r<6
Sector with area = pi …………………. 140 deg
Opposite to star …………………. blank circle</p>

<p>Experimental ? Section 4 for me</p>

<p>Set with the greatest element …………………. < 99
a question about a pentagon…and a circle trying to touch it
scatterplot…where u had to count how many trees</p>

<p>no one has been able to explain the 4/3 slope for the tangent question…</p>

<p>im pretty sure the rectangle area decreases by 1 percent</p>

<p>was the tangent the one with the perpendicular?</p>

<p>“Area increase …………………. 1% (wasn’t it decrease?!)”</p>

<p>I thought it was decrease. .9x1.1 is equal to .99 meaning there is a decrease.</p>

<p>definitely decrease 1%</p>

<p>differentiate x^2+y^2=25 and plug in the point (-4,3)</p>

<p>scatterplot one was 32 trees
the tangent one as 4/3</p>

<p>the line didnt interset at 0,0 though
so the slope cant be -4,3 right</p>

<p>Okay explanation for the tangent question:</p>

<p>If you draw a dotted line from the point of intersection down to the x axis, you can form a 3-4-5 triangle with the radius of the circle. This means that the radius is perpendicular to the line. Because you know it’s 3-4-5, you know the y value of the point of tangent. Knowing this, you can find the slope of the radius from the point to the origin. Since the line is perpendicular to that, the slope is the negative reciprocal. Which is 4/3.</p>