A right cylinder has a base radius of 1 cm and a height of 3 cm. What is its lateral area in square centimetres.
一个直圆柱底面半径是1厘米，高是3厘米．它的侧面积是多少平方厘米．
<gadget id="calculator">2 * 3.14 * 1 * 3</gadget>
<output>18.84</output>

<result>18.84</result>