沙堆的体积:
1
3 ×3.14×(9.42÷3.14÷2) 2×2,
=
3 ×3.14×1.5 2×2,
3 ×3.14×2.25×2,
=4.71(立方米);
沙堆的重量:
4.71×2=9.42≈9(吨);
答:这堆砂约重9吨.