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GRE Math: Common Errors

Subjects : gre, math

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. x^(-y)=
Sector area = (n/360) X (pi)r^2
From northeast - counterclockwise. I - II - III - IV
31 - 37
1/(x^y)

2. The ratio of the areas of two similar polygons is ...
72
... the square of the ratios of the corresponding sides.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
No - only like radicals can be added.

3. 0^0
Undefined
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
18
16.6666%

4. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
F(x) + c
16.6666%
A reflection about the origin.
$3 -500 in the 9% and $2 -500 in the 7%.

5. What is the area of a regular hexagon with side 6?
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
The greatest value minus the smallest.
180
F(x-c)

6. (6sqrt3) x (2sqrt5) =
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
3sqrt4
A subset.
II

7. Pi is a ratio of what to what?

8. Volume for a cylinder?
13
Area of the base X height = (pi)hr^2
5
Two angles whose sum is 90.

9. What is the side length of an equilateral triangle with altitude 6?
2.4. We calculate the area (6) and then turn the triangle on its side and use x as the height to calculate again. (5x)/2=6
4sqrt3. The triangle can be divided into two equal 30-60-90 triangles with side 6 as the side in which 6 = xsqrt3. So x =2sqrt3...
Infinite.
C = (pi)d

10. a^2 + 2ab + b^2
The union of A and B.
(a + b)^2
The curve opens downward and the vertex is the maximum point on the graph.
The set of input values for a function.

11. 70 < all primes< 80
9 : 25
71 - 73 - 79
Sector area = (n/360) X (pi)r^2
90pi

12. There are 10 finalists for the school spelling bee. A first - second - and third place trophy will be awarded. How many different people can get the three prizes?
$3 -500 in the 9% and $2 -500 in the 7%.
A chord is a line segment joining two points on a circle.
10! / 3!(10-3)! = 120
2 & 3/7

13. Area of a triangle?
(amount of decrease/original price) x 100%
(a + b)^2
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
(base*height) / 2

14. If Madagascar'S exports totaled 1.3 billion in 2009 - and 4% came from China - what was the value in millions of the country'S exports to China?
52
A reflection about the axis.
The curve opens upward and the vertex is the minimal point on the graph.
A = pi(r^2)

15. What is the sum of the angles of a triangle?
20.5
Its divisible by 2 and by 3.
Divide by 100.
180 degrees

16. To convert a percent to a fraction....
9 & 6/7
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
10! / 3!(10-3)! = 120
Divide by 100.

17. What is the 'Range' of a function?
x^(6-3) = x^3
A subset.
(a - b)^2
The set of output values for a function.

18. Simplify 9^(1/2) X 4^3 X 2^(-6)?
The curve opens upward and the vertex is the minimal point on the graph.
3
(a - b)(a + b)
3 - -3

19. Which is greater? 200x^295 or 10x^294?
Relationship cannot be determined (what if x is negative?)
288 (8 9 4)
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
Part = Percent X Whole

20. What is a central angle?
A central angle is an angle formed by 2 radii.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
Ax^2 + bx + c where a -b and c are constants and a /=0
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]

21. Evaluate (4^3)^2
III
Cd
4096
180 degrees

22. What does scientific notation mean?
A central angle is an angle formed by 2 radii.
Yes. [i.e. f(x) = x^2 - 1
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
Arc length = (n/360) x pi(2r) where n is the number of degrees.

23. T or F? Given d -e &f =/ 0 - [(d^3)e(f^5)] / 2d(e^3) / [3(d^2)(e^3)(f^7)] / [6(e^5)(f^2)]?
4a^2(b)
$3 -500 in the 9% and $2 -500 in the 7%.
An expression with just one term (-6x - 2a^2)
True

24. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
1:sqrt3:2
Yes. [i.e. f(x) = x^2 - 1
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
3

25. Hector invested $6000. Part was invested in account with 9% simple annual interest - and the rest in account with 7% simple annual interest. If he earned $490 in the first year of these investments - how much did he invest in each account?
28. n = 8 - k = 2. n! / k!(n-k)!
Sector area = (n/360) X (pi)r^2
From northeast - counterclockwise. I - II - III - IV
$3 -500 in the 9% and $2 -500 in the 7%.

26. Can you simplify sqrt72?
The third side is greater than the difference and less than the sum.
An angle which is supplementary to an interior angle.
4096
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

27. What is the surface area of a cylinder with radius 5 and height 8?
4.25 - 6 - 22
130pi
The union of A and B.
20.5

28. How to find the diagonal of a rectangular solid?
0
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
130pi
The set of elements found in both A and B.

29. What is the slope of a vertical line?

30. Solve the quadratic equation ax^2 + bx + c= 0
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
2.4. We calculate the area (6) and then turn the triangle on its side and use x as the height to calculate again. (5x)/2=6
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
(a + b)^2

31. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
3/2 - 5/3
413.03 / 10^4 (move the decimal point 4 places to the left)
(a + b)^2
28. n = 8 - k = 2. n! / k!(n-k)!

32. What is the 'Range' of a series of numbers?
The greatest value minus the smallest.
Yes. [i.e. f(x) = x^2 - 1
The set of output values for a function.
The empty set - denoted by a circle with a diagonal through it.

33. The larger the absolute value of the slope...
180 degrees
1 & 37/132
The steeper the slope.
6

34. Can the output value of a function have more than one input value?
Yes. [i.e. f(x) = x^2 - 1
An arc is a portion of a circumference of a circle.
72
(a + b)^2

35. What is the absolute value function?
G(x) = {x}
Undefined - because we can'T divide by 0.
Its last two digits are divisible by 4.
1

36. 5/6 in percent?
9 & 6/7
4:5
83.333%
x(x - y + 1)

37. The perimeter of a square is 48 inches. The length of its diagonal is:
12sqrt2
Two angles whose sum is 180.
4096
1/a^6

38. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
4.25 - 6 - 22
(a + b)^2
8

39. Circumference of a circle?
Diameter(Pi)
1.0843 X 10^11
Undefined
The set of input values for a function.

40. What is a minor arc?

41. What are congruent triangles?
Triangles with same measure and same side lengths.
2 & 3/7
The objects within a set.
The curve opens downward and the vertex is the maximum point on the graph.

42. Legs: 3 - 4. Hypotenuse?
1
5
An arc is a portion of a circumference of a circle.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

43. Legs 5 - 12. Hypotenuse?
13
2 & 3/7
$3 -500 in the 9% and $2 -500 in the 7%.
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.

44. 10^6 has how many zeroes?
90 degrees
6
x^(4+7) = x^11
180

45. Factor x^2 - xy + x.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
x(x - y + 1)
2^9 / 2 = 256
An isosceles right triangle.

46. Formula for the area of a sector of a circle?
Members or elements
Sector area = (n/360) X (pi)r^2
Arc length = (n/360) x pi(2r) where n is the number of degrees.
441000 = 1 10 10 10 21 * 21

47. What is the ratio of the sides of a 30-60-90 triangle?
4725
4.25 - 6 - 22
x(x - y + 1)
1:sqrt3:2

48. What are 'Supplementary angles?'
90pi
Two equal sides and two equal angles.
3sqrt4
Two angles whose sum is 180.

49. x^4 + x^7 =
The empty set - denoted by a circle with a diagonal through it.
x^(4+7) = x^11
1
37.5%

50. P and r are factors of 100. What is greater - pr or 100?
.0004809 X 10^11
An arc is a portion of a circumference of a circle.
Area of the base X height = (pi)hr^2
Indeterminable.