(pi = = 3.141592...)
Areas
square = a2
rectangle = ab
parallelogram = bh
trapezoid = h/2 (b1 + b2)
circle = pi r 2
ellipse = pi r1 r2
triangle = (1/2) b h
equilateral triangle = (1/4)(3) a2
triangle given SAS = (1/2) a b sin C
triangle given a,b,c = [s(s-a)(s-b)(s-c)] when s = (a+b+c)/2 (Heron's formula)
regular polygon = (1/2) n sin(360°/n) S2
when n = # of sides and S = length from center to a corner
Volumes
cube = a3
rectangular prism = a b c
irregular prism = b h
cylinder = b h = r2 h
pyramid = (1/3) b h
cone = (1/3) b h = 1/3 r2 h
sphere = (4/3) r3
ellipsoid = (4/3) pi r1 r2 r3
Surface Areas
cube = 6 a2
prism:
(lateral area) = perimeter(b) L
(total area) = perimeter(b) L + 2b
sphere = 4 r2
Tuesday, March 2, 2010
ALGEBRA FORMULAS
(a+b)2 = a2 + 2ab + b2
(a+b)(c+d) = ac + ad + bc + bd
a2 - b2 = (a+b)(a-b) (Difference of squares)
a3 b3 = (a b)(a2 ab + b2) (Sum and Difference of Cubes)
x 2 + (a+b)x + ab = (x + a)(x + b)
if ax2 + bx + c = 0 then x = ( -b (b2 - 4ac) ) / 2a (Quadratic Formula)
(a+b)(c+d) = ac + ad + bc + bd
a2 - b2 = (a+b)(a-b) (Difference of squares)
a3 b3 = (a b)(a2 ab + b2) (Sum and Difference of Cubes)
x 2 + (a+b)x + ab = (x + a)(x + b)
if ax2 + bx + c = 0 then x = ( -b (b2 - 4ac) ) / 2a (Quadratic Formula)
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