A cylinder has a base radius of 3 cm and a height of 15 cm, what is its surface area in square centimeters?
一个圆柱体，底面半径是3厘米，高是15厘米，它的表面积是多少平方厘米．
<gadget id="calculator">2 * 3.14 * 3 * 15</gadget>
<output>282.6</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9 * 2</gadget>
<output>56.52</output>

<gadget id="calculator">282.6 + 56.52</gadget>
<output>339.12</output>

<result>339.12</result>