GRE math Flashcards
a^2 x a^3
a5
a^9 / a^2
a^7
(a^2)^4
a^8
a^0
1
m^-s
1/m^s
m^(x/y)
(y square root m)^x
n^(1/2)
square root n
square root of 2
1.4
square root of 3
1.7
Division by zero
Can’t be done
Prime factorization:
210= 2 x 105 = 2 x 3 x 35 = 2 x 3 x 5 x 7
Like radicals can be
Added/subtracted
a/b / c/d =
a/b x d/c
2/3 reciprocal
3/2 > 1 & 2/3
-2/3 reciprocal
-3/2 < 1 & -2/3
(1/2)^2
1/4 < 1/2
(-1/2)^2
1/4 > 1/2
Distance
Speed x time
Speed
Distance x time
Time
Quantity/Rate
When can you average averages?
Only if an equal number of terms in each set
A U B
Both A & B
|A U B|
|A| + |B| - |A xUx B|
How many ways are possible?
Each space must be filled (ie in 1st place 7 options, in 2nd place 6 options)
P(A or B)=
P(A) + P(B) - P(A + B)
Rectangle area
LxW
Rectangle perimeter
2L + 2W
Rectangle volume
LWH
Square area
s^2
Square perimeter
4s
Square volume
H x S^2
Circle area
Pi x r^2
Circle circumference
2 x pi x r
Circle volume
Pi x r^2 x h
Parallelogram area
Bh
Parallelogram perimeter
sum of sides
Parallelogram volume
BhH
Sum of interior angles of a polygon
(n-2) x 180 (n = number of sides)
Sum of angles on a line
180
Sum of complimentary angles
90
Sum of supplementary angles
180
Sum of angles in a triangle
180
In crossing parallel lines what angles are equal?
Across from each other
In isosceles triangle what angles are equal?
Adjacent to equal sides
30-60-90 rule
sides: x, 2x, x root 3
45-45-90 rule
sides: x, x, x root 2
Triangle side rules
3-4-5; 5-12-13; 7-24-25; 8-15-17
If a & b are angles inside a triangle what is the outside angle across?
a+b
Area of sector in a circle
n/360(pi r^2); n is degree of angle
Slope
m = (Y2-Y1)/(X2-X1)= rise/run
Equation of a line
y = mx + b; m= slope, b= y intercept
Cylinder volume
Pi x r^2 x h
Cylinder surface area (lateral)
2 x pi x r x h
Total surface area
(2 x pi x r^2) + (2 x pi x r x h)
