The radius of the base of a log is 2dm, and the height is 12dm. How much dm does the surface area increase after sawing it into 4 sections?**2.
一根圆木底面半径为2dm，高为12dm，把他锯成4段后表面积增加了多少dm**2．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 6</gadget>
<output>75.36</output>

<result>75.36</result>