Math – formula

[Ref http://www.math.com/tables/geometry/areas.htm] Area [面積] square = a 2 rectangle = ab parallelogram 平行四邊形 = bh trapezoid 梯形 = h(b1 + b2)/2 circle = pi r 2 ellipse = pi r1 r2 triangle = bh/2 equilateral triangle = [(√3)/4]( a 2 )   Perimeter [圓周] square = 4a rectangle = 2(a+b) triangle = a + b + c circle = 2pi r    Volume [體積] cube = a 3 rectangular prism = = a b c cylinder =  pi r 2 h pyramid = (1/3) b h cone = … Continue reading Math – formula