GRE Math Formulas

Question 0

Circumference of a circle

Answer 0

2 pi r
-or-
Pi diameter

Question 1

Area of a circle

Answer 1

Pi r square

Question 2

Area of a triangle

Answer 2

1/2 base x height

Question 3

Ratio of an Isosceles right triangle

Answer 3

1:1:square root of 2

Question 4

Ratio of a 30-60-90 Triangle

Answer 4

1:square root of 3:2

Question 5

Rectangular volume

Answer 5

L x w x h

Question 6

Cylindrical volume

Answer 6

Pi r square x height

Question 7

Third side of a triangle

Answer 7

Less than the sum of the other two sides
-and-
Greater than the absolute value of side 1-side 2

Question 8

Pythagorean triples

Answer 8

3: 4:5
5: 12:13
7: 24:25
8: 15:17

Question 9

Equation of a line

Answer 9

y=mx+b

y=(slope*x) + (y intersect)

Question 10

Slope formula

Answer 10

y^2-y^1/x^2-x^1

Rise / run

Question 11

Point-slope formula

Answer 11

y-y^0=m(x-x^0)

Question 12

2 cubed

Answer 12

8

Question 13

3 cubed

Answer 13

27

Question 14

4 cubed

Answer 14

64

Question 15

5 cubed

Answer 15

125

Question 16

First ten primes

Answer 16

2,3,5,7,11,13,17,19,23,29

Question 17

Total of angles in an n-sided polygon

Answer 17

(n-2)(180)

Question 18

Percent change formula

Answer 18

Change
——— x 100
Original

Question 19

Multiplying exponential terms with the same base

2^2 x 2^6

Answer 19

Add the exponents

2^2 x 2^6 = 2^8

Question 20

Dividing exponential terms with the same base

2^6 / 2^2

Answer 20

Subtract the exponents

2^6 / 2^2 = 2^4

Question 21

Raising an exponential term to another power

(2^2)^3

Answer 21

Multiply the exponents

(2^2)^3 = 2^6

Question 22

Negative exponent

5^-8

Answer 22

Rewrite in reciprocal form with positive exponent

5^-8 = 1 / 5^8

Question 23

Scientific notation

Positive exponent

Answer 23

Decimal moves forward to the right the number of spaces indicated by the exponent

Question 24

Scientific notation

Negative exponent

Answer 24

Decimal moves backward to the left the number of spaces indicated by the exponent

Question 25

Fractions in an exponent

Answer 25

Divide–as in roots–instead of multiply

Question 26

Multiplying square roots

Answer 26

Multiply the numbers and put the result under a new square root sign

Question 27

What happens to the inequality sign when multiplying or dividing both sides by a negative number?

Answer 27

The inequality sign is flipped

Question 28

Isosceles right triangle

Answer 28

45-45-90

1:1:square root of 2

Question 29

30-60-90 triangle

Answer 29

Right triangle

1:square root of 3:2

Question 30

Area of a parallelogram

Answer 30

2 x 1/2 base x height
(Because it is two triangles)
Need to find height as perpendicular to base

Question 31

How to determine the x-intercept from the equation of a line

Answer 31

When crossing the x-axis, value of y will be 0. Plug in “0” for y and solve for x.

Question 32

Group formula

Answer 32

Total=[group 1] + [group 2] - [both] + [neither]

Question 33

Bell curve/normal distribution

Answer 33

34-14-2

Question 34

Dividing Factorials:

8! / 10!

Answer 34

8! / 10! = 1 / 10 x 9
Because everything in 8! cancels out those same numbers that are included in 10!, making the numerator “1”, and leaving only the “9” and “10” that are not included in 10! in the denominator.