A cylinder has a base circumference of 28 cm and a height of 5 cm. What is its lateral area in cm**2.
一个圆柱，底面周长是28厘米，高是5厘米，它的侧面积是多少厘米**2．
<gadget id="calculator">28 * 5</gadget>
<output>140</output>

<result>140</result>