An arco book arco is a registered trademark of Thomson Learning, Inc., and is used herein under license by Peterson’s. About The Thomson Corporation and Peterson’s

Mathematics Level IC/IIC Subject Tests
247
ARCO
■ SAT II Subject Tests
w w w . p e t e r s o n s . c o m / a r c o
So the area of the equilateral triangle is:
Area
=






( )
=
=
1
2
6
2
2
12
4
3
2
And the total surface area of the fragment is:
Area
= +
= +
= +
=
3
2
3
2
3
3
2
3 1 73
2
2 36
.
.
48. The correct answer is (E). [0] A parabola is the locus of all points that are equidistant from a fixed
point called the focus and a certain fixed line (that does not include the focus) called the directrix.
Given the focus and the directrix, it is possible to find the equation that describes a certain parabola
by using the distance formula.
The distance of any point (x,y) on this parabola from the focus is:
And the distance from that same point to the directrix is just the change in the y–coordinate:
d = y – 0
So the equation that describes the parabola is:
Square both sides of the equation:
(x – 2)
2
+ (y – 3)
2
= y
2
And:
(x – 2)
2
+ (y
2
– 6y + 9) = y
2
(x – 2)
2
– 6y + 9 = 0
(x – 2)
2
= 6y – 9
(x – 2)
2
= 3(2y – 3)

---

Lesson 8
248
w w w . p e t e r s o n s . c o m / a r c o
ARCO
■ SAT II Subject Tests
49. The correct answer is (D). [0] The probability of exactly x results out of n events is given by the
formula:
n
C
x
[P(A)]
x
[P(B)]
n – x
Where 
n
C
x
is the number of combinations of n things taken x at a time, P(A) is the probability of the
occurrence of the event, and P(B) is the probability of the nonoccurrence of the event. Here the probability
of the student’s getting a correct or an incorrect answer on any given item is 1/2 and there are 3 such items: