cylinder has a base radius of 4 cm and a height of 1 dm, what is the surface area of the cylinder?
一个圆柱的底面半径是4cm，高是1dm，这个圆柱的表面积是多少．
<gadget id="calculator">3.14 * 4 * 2 * 1 * 10</gadget>
<output>251.2</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16 * 2</gadget>
<output>100.48</output>

<gadget id="calculator">251.2 + 100.48</gadget>
<output>351.68</output>

<result>351.68</result>