Cong Cong plans to make a cylindrical pen holder with a base radius of 5cm and a height of 12cm, all made of artificial leather, how many cm should be used for artificial leather**2.
聪聪计划做一个底面半径5cm，高12cm的圆柱形笔筒，全用人造革做，要用人造革多少cm**2．
<gadget id="calculator">2 * 3.14 * 5 * 12</gadget>
<output>376.8</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">376.8 + 78.5</gadget>
<output>455.3</output>

<result>455.3</result>