A cylindrical chimney is made from a piece of iron sheet with a length of 3.5 meters and a width of 2.5 meters. What is the lateral area of the chimney? (interfaces are ignored)
用一张长3.5米，宽2.5米的铁皮做一个圆柱烟筒，这个烟筒的侧面积是多少？(接口忽略不计)
<gadget id="calculator">3.5 * 2.5</gadget>
<output>8.75</output>

<result>8.75</result>