The radius of the base of a cylinder is 3cm and the height is 4cm, what is its lateral area in cm**2.
一个圆柱的底面半径是3cm，高是4cm，它的侧面积是多少cm**2．
<gadget id="calculator">3.14 * 3 * 2 * 4</gadget>
<output>75.36</output>

<result>75.36</result>