There is a cylinder whose bottom diameter is 10cm. If the height increases by 2cm, how much does the side area increase in cm**2.
有一个圆柱，底面直径是10cm，若高增加2cm，则侧面积增加多少cm**2．
<gadget id="calculator">3.14 * 10 * 2</gadget>
<output>62.8</output>

<result>62.8</result>