小学所有几何图形的公式

正方形A边长c = 4as = a2矩形A和B边长c = 2 (a+b) s = ab三角形A，B，C边长h-A，B，C-内角其中s =(A+B+C)/2s = ah/2 = ab/2 sinc =[s(s-A)(s-B)(s-C)]1/2 = a2 sinb sinc/(2 Sina)四边形d， d. B边长H-A边高α-夹角S = ah = ABS in α菱形A边长α-夹角D-长对角线长D-短对角线长S = DD/2 = A2Sinα梯形A和B-上下底长H-高M-中线长S = (a+b) H/2 = MH圆R-半径D. 4扇形R-扇形半径A-圆心角度数C = 2r+2π r× (a/360) s = π r2× (a 2 =παR2/360-b/2[R2-(b/2)2]1/2 = R(L-b)/2+BH/2≈2bh/3环R-外圆半径R-内圆直径D-内圆直径S = π。