cylinder has a base diameter of 4 cm and a height of 6 cm, find the surface area.
一个圆柱体，底面直径4厘米，高6厘米，求表面积．
<gadget id="calculator">3.14 * 4 * 6</gadget>
<output>75.36</output>

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

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

<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<gadget id="calculator">75.36 + 25.12</gadget>
<output>100.48</output>

<result>100.48</result>