SAT math formulas and shortcuts

Slope of a standard form linear equation (Ax+By=C)

-A/B

sum of the solutions of a quadratic in ax²+bx+c form

-b/a

Y-int of a standard form linear equation (Ax+By=C)

C/B

slope of parallel lines

Parallel lines have the same slope-- no solution if y-int is different

Discriminant

b²-4ac discriminant>0 : 2 solutions discriminant=0 :1 solution discriminant<0 : no solution

product of the solutions of a quadratic in ax²+bx+c form

c/a

percent formula (exp growth and decay)

finalamount = orginal(1 +/- Rate) ^ #ofchanges

multiple formula (exp growth and decay)

finalamount= original(multiplier)^#ofchanges

slope of perpendicular lines

negative reciprocal slopes (ex. 4/5 --> -4/5)

relationship between sine and cosine angle

the cosine of an angle is equal to the sine of it's complimentary angle

relationship between an arc and its sector's angle

the ratio of the {length of an arc : circle's circumference} is equal to {x degrees: 360 degrees} ex: Circle with arc BC=2/5 and sector angle x 2/5 = x/360