2、36 8
3、6
5、25. 12(8π)
Analysis of 1, 6×5×8=240
2,24 ÷ 4 = 6,6× 6 = 36 (a square has four sides) 24 ÷ 12 = 2,2× 2× 2 = 8 (a cube has12 sides).
3. Cylinder-cone =12s× h-1/3× s× h =12sh =18 Cone volume: 1/3 s h=6.
5、s = 2πr×l = 2×π×0.5×8 = 8π= 25. 12