Math Rules Flashcards
what is the area of a triangle
A=(1/2)bh
what is the area of a rectangle
A=bh
what is the area of a trapezoid
A=(1/2)(b1+b2)(h)
what is the area of a circle
A=pi*r^2
what is the circumference of a circle
C=2pir
How do you calculate the volume of a cylinder or cube?
Take the area of the base X the height
What is the equation to find the mean of a group of numbers?
(mean = average) = (sum of #)/(total number of #)
What is the “mode” of a group of numbers?
the value that recurs the most
What is the “median” of a group of numbers?
the middle value when in order
What is the “range” of a group of numbers?
The largest # minus the smallest #
In an arithmetic sequence, you ___ to get the next term, while in a geometric sequence you _____ to get the next term.
arithmetic = add geometric= multiply
How do you find the reciprocal of a fraction?
You flip it over,
i.e. 2 -> 1/2
and 4/3 -> 3/4
etc.
What is/ how do you use the triple fraction method?
method:
(A/B)=(fact #1 for A / fact #1 for B) = (fact #2 for A / fact #2 for B)
use:
This is used for math problems where a constant relationship is metioned. For ex: Car A is driving at 2mph while car B drives at 3mph. If the speed relationship is maintained, and car A increases its speed to 4mph how fast must car B be going?
(2/3)=(4/x) -> x=6mph
USE THIS FOR ALL RELATION PROBLEMS
What is the probabilty that an event “x” happens, when the total number of possible events is “y”?
probability = (# of winners)/(total)=x/y
what is the equation for a line
y=mx + b
what is the equation for the slope of a line
slope=m=rise/run=(y2-y1)/(x2-x1)
What is “b” in the equation y=mx+b
b is the y-intercept, in other words, this is the value of y when x=0
When two lines are parallel their slopes ____ while when they are perpendicular their slopes _____
parallel lines: slopes are the same
perpendicular lines: slope= the negative reciprocal of the other line
To add or subtract fractions, first:
manipulate the fractions to have a common denominator. After this they can be added/subt. as follows:
ex: (1/2) + (3/4) = (2/4)+(3/4) =(5/4)
To multiply fractions
multiply the top number together to get the numerator and the bottom numbers together to get the denominator. ex) (1/2)*(3/4)= (3/8)
3/(2/5) = ? (in other words how do you divide by a fraction)
To divide by a fraction, multiply by the reciprocal:
3/(2/5)= 3 * (5/2) = (15/2)
what is the scientific notation of 300454?
3.00454 * 10 ^5
How do you FOIL? ex) (x+1)(x-2)=0
(x+1)(x-2)= 0
x^2 -2x +1x-2=0
reduce: x^2 -x -2 =0