A: The volume of wood is 2260.8 cubic centimeters.

General calculation can be done 8 times, and precise arrangement can be done 9 times.

First, the width of the iron sheet is 3m=30dm, and the length is 10m= 100dm. A barrel is a cylinder without a cover, with only a bottom and sides. The area of the bottom surface is S bottom = π d 2/4 = π× 6 2/4 = 9 π.

The side length =πDh=π×6× 15=90π and the size is 15× 18.9.

Because the width of the material is 30, and the cutting size of 15 is just two pieces side by side, we can consider cutting 4×2=8 pieces first, then the length is 18.9×4=75.6, and the rest.

For the rest of 100-75.6=24.4, 1 edges can be cut horizontally, that is, 15 is added in the length direction, and * * * is 75.6+ 15=90.6.

* * * Cut off 4×2+ 1=9 edges. Width direction is 30-18.9 =11.1. The layout of the bottom surface is as follows:

At the position where the remaining length is 100-90.6=9.4, according to the far angle of the first circle (the angle away from the cutting part), the connecting line of the second circle is placed at the position with a width of 30, so that the width of the two rows of circles is (2+ 1/2) × 3 = 7.5.