Math Formulas Flashcards
Square - Perimeter
P = 4s
Multiply any one side by four
Square - Area
A = s^2
Square one side
Cube - Volume
V = lwh
length * width * height
AKA prism, rectangles
Rectangle - Area
A = lw
length * width
Rectangle - Perimeter
P = 2l + 2w
multiply the length by 2 & width by 2 & add
Prism - Surface Area
A = 2(lw + wh + lh)
Circle - Circumference
C = 2πr
OR
C = πd
depending on your info.
two radii equal the diameter, so 2r = d
Circle - Area
A = πr^2
Cylinder - Area
Lateral area (side) = 2πrh
=> 2πradius*height
total area = 2πrh + 2πr^2
=> this combines the lateral area plus the area of the two circles (which is why the area is multiplied by 2)
Cylinder - Volume
V = πr^2h
– it’s just circle area times height
Triangle - Pythagorean Theorem
a^2 + b^2 = c^2
a & b are legs, c is hypotenuse
Triangle - Area
A = 1/2bh
1/2 * base * height
Pyramid - Volume
V = 1/3bh
volume = 1/3 * b * height
Trapezoid - Area
A = 1/2(b + b’)h
area = 1/2 (top base + bottom base) * height
Parallelogram
A = bh
Distance
D = rt
– multiply the rate (r) by the time (t) to find the distance (D)
r = D / t
OR
t = D / r
Slope of a Line
y = mx + b
aka: y = slope*x + y-intercept
mx => slope
x & y => pair of coordinates
b => y-intercept, where the line passes through the y-axis
Calculating slope (rise over run)
m = y2 - y1 / x2 - x1
OR
slope = rise / run
(2, 3) (4, 6)
(6 - 3) / (4 - 2) = 3 / 2
Average
AVG = sum of numbers / # of terms
aka “mean”
Mean, Median, Mode, Range
Mean ==> average
Median ==> middle # of data set
Mode ==> most common number of a data set
Range ==> the difference between the highest # and the lowest #
Probability
probability of an event occurring = # of successful outcomes / total # of possible outcomes
Percent Increase
[(final amount - original amount) / original amount] * 100%
Percent Decrease
[(original amount - final amount) / original amount] * 100%
Hexagon - Area
A = (3√3 / 2)a^2
a = one side of hexagon
sum of all angles = 720 => 720/6 = 120
Pentagon - Area
A = 1/4 (√5(5 + 2√5)a^2
Note: “5(5 + 2√5) are all under the square root
a = side
sum of all angles = 540 => 540/5 = 108
Octagon - Area
A = 2(1 + √2)a^2
a = side
sum of all angles = 1080 => 1080/8 = 135
Decagon - Area
A = (5/2)a^2 * √5 + 2√5
Note: “5 + 2√5” are all under square root
a = side
sum of all angles = 1440 => 1440/10 = 144