Volumes+and+Surface+Areas+2

** pi  //= 3.141592..//**

Areas
square = a^2 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) a^2 triangle given SAS = (1/2) a b sin C triangle given a,b,c = Sqrt//[s(s-a)(s-b)(s-c)] when s = (a+b+c)/2 **(Heron's formula)** regular polygon = (1/2) n sin(360°/n) S^2 when n = # of sides and S = length from center to a corner



Volumes
cube = a^3 rectangular prism = a b c irregular prism = **b** h cylinder = **b** h = pi //r^2 h pyramid = (1/3) **b** h cone = (1/3) **b** h = 1/3 pi// r^2 h sphere = (4/3) pi //r^3 ellipsoid = (4/3)// pi //r1 r2 r3 //



Surface Areas
cube = 6 a^2 prism: (lateral area) = perimeter(**b**) L (total area) = perimeter(**b**) L + 2**b** sphere = 4 pi r^2 Source: http://math2.org/math/geometry/areasvols.htm