Geometry

clankjewishElectronics - Devices

Oct 10, 2013 (4 years and 3 days ago)

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SAT
Formulas, Definitions, and Theorems


Geometry


Similar Triangles:

Corresponding angles are equal in measurement and corresponding
sides are proportional.


Equilateral Triangles:

all three angles measure 60 degrees and all three sides are
congruent.


Ve
rtical angles

>< are congruent.


Supplementary

angles add to 180 degrees.


Complementary

angles add to 90 degrees.


Area of a square:

s^2


Slope of a line:

(Y
2



Y
1
)/(X
2



X
1
) = m


Equation of a line:

y = mx + b, where m is the slope and b is the y
-
interce
pt.


The sum of the
interior angles of a polygon

= (n
-

2) x 180, where n = the number of
sides.


Algebra


Direct Proportionality:

y is directly proportional to x if y = kx, for some constant k.


Inverse Proportionality:

y is inversely proportional to x if

y = k/x, for some constant k.


Factoring the
difference of two squares
: a^2
-

b^2 = (a + b)(a


b)


The
distribution

of (x + y)^2 = x^2 + 2xy + y^2


Converting
exponents to roots
: x^(1/2) = √x and x^(1/3) =
3
√x


Numbers & Operations


Sum of Consecutive Integers:

x + (x+1) + (x+2) + (x+n), where (x+n) represents the last
integer.


Distance

= rate x time


Percents:

a% of n = a/100 x n


Percent Change:

(original amount


new amount)/
original amount x 100%


Rational Number:

a number that can be expressed as a ratio of two integers


Irrational Number:

a number that cannot be precisely expressed as a fraction or decimal
(ex. √2, √3,
Π
)


Domain:

the set of values for which a function is

defined. For the function y = f(x), the
domain is the set of all x values for which f(x) is defined.


Range:

the set of outputs, or results, of the function. For the function y = f(x), the range
is the set of all possible y values.


Statistics/Data Anal
ysis/Probability


Permutation:

The number of ways to organize r out of n different objects (order matters)
= n!/(n
-
r)!


Combination:

The number of combinations of r out of n different objects (order does not
matter) = n!/[(n
-
r)!r!]


Average/mean:

sum of al
l data points/total number of data points