There is a cylinder whose base diameter is 12 cm. If the height increases by 2 cm, the lateral area increases by π square centimeters.
有一个圆柱，底面直径是12厘米，若高增加2厘米，侧面积就增加多少π平方厘米．
<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<result>24</result>