设RT三角形ABC,〈A=90度,作AD⊥BC,垂足D,AB=4,AC=3,BC=5,
BC*AD/2=AB*AC/2=S△ABC,
AD=12/5,
以斜边为轴旋转一周,所形成的立体是以AD为底半径,高分别是BD和DC的两个圆锥体,
V=πAD^2*BD/3+πAD^2*CD/3
=πAD^2*BC/3
=48π/5.