The radius of the base of a cylinder is 4 cm. If the cylinder is cut into two parts of equal size along the height, the cut surface is exactly a square. What is the surface area of this cylinder?
一个圆柱的底面半径是4厘米．如果沿着高将这个圆柱切成大小相等的两部分，切面恰好是正方形．这个圆柱的表面积是多少？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">3.14 * 8 * 8</gadget>
<output>200.96</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">200.96 + 100.48</gadget>
<output>301.44</output>

<result>301.44</result>