If the lateral expansion of a cylinder is a square, the radius of the base of the cylinder is 2 cm, what is the surface area of the cylinder?
一个圆柱的侧面展开是一个正方形，圆柱的底面半径是2cm，圆柱的表面积是多少．
<gadget id="calculator">3.14 * 2 * 2</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 * 12.56</gadget>
<output>157.7536</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">157.7536 + 25.12</gadget>
<output>182.8736</output>

<result>182.8736</result>