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Flashcards: Common math formulas
Average
sum/total number
Area of a circle
πr²
Circumference of a circle
2πr
Arc
circumference(central angle/360)
Sector
area(central angle/360)
Compound interest
A = P (1 + r/n)^ (nt) A = accumulated amount P = principle r = interest rate expressed as decimal n = compounding per period t = number of periods
Exponential growth
y = C(1+r)^t y = final amount C = initial amount r = rate of change t = time
Exponential decay
y = C(1-r)^t y = final amount C = initial amount r = rate of change t = time
Cone volume
(1/3)πr²h
Cylinder volume
πr²h
Cylinder surface area
2πrh+2πr²
Regular prism volume
lwh
Rectangular prism surface area
2lw+2lh+2wh
Rectangular pyramid volume
(1/3)lwh
Sphere volume
(4/3)πr³
equation of a circle
(x-h)² + (y-k)² = r² h = x coordinate of the centre point k = y coordinate of the centre point
parabola standard form
ax² + bx + c
Quadratic formula
x = [-b ± √(b² - 4ac)}/2a
Rhombus area
Bh
Rhombus Perimeter
2b + 2h
Trapezoid area
A = (b1+b2)½h
Polygon interior angles
(n-2)180
Ratio formula
one part/another part
Direct proportional relationship
one part/whole part = one part / whole part
Probability
desired outcomes/total outcomes
Area of a triangle
½bh
Pythagorean Theorem
a²+b²=c²
slope
m = rise/run m = ∆y/∆x m = (y₂-y₁)/(x₂-x₁)
slope intercept form
y=mx+b
% change
change/original