If the circumference of the base of a cylinder is 31.4 cm and the height is 4 cm, what is its lateral area in square centimeters?
一个圆柱的底面周长是31.4厘米，高是4厘米，它的侧面积是多少平方厘米．
<gadget id="calculator">31.4 * 4</gadget>
<output>125.6</output>

<result>125.6</result>