cylindrical tea bucket has a bottom circumference of 31.4 cm and a height of 25 cm. What is its lateral area.
一个圆柱形茶叶桶，底面周长是31.4cm，高是25cm．它的侧面积是多少．
<gadget id="calculator">31.4 * 25</gadget>
<output>785</output>

<result>785</result>