To make a cylindrical tin chimney, the length of the chimney is 1 meter, the diameter is 15 cm, and the welding area is 1 cm. How many square centimeters of iron skin is needed to make such a chimney?
制作一节圆柱形铁皮烟囱，烟囱长1米，直径15厘米，焊接的地方为1厘米，制作这样的烟囱至少需要多少平方厘米的铁皮？
<gadget id="calculator">3.14 * 15</gadget>
<output>47.1</output>

<gadget id="calculator">47.1 + 1</gadget>
<output>48.1</output>

<gadget id="calculator">48.1 * 1 * 100</gadget>
<output>4_810</output>

<result>4_810</result>