A cylindrical bucket without a cover, with a bottom diameter of 40 cm and a height of 70 cm, should be painted with a layer of anti-rust paint inside and outside the bucket. How many square decimeters is the painted area?
一个无盖的圆柱形水桶，底面直径40厘米，高70厘米，要在这个水桶的里外都图上一层防锈漆．涂漆的面积有多少平方分米？
<gadget id="calculator">40 / 2 / 10</gadget>
<output>2</output>

<gadget id="calculator">70 / 10</gadget>
<output>7</output>

<gadget id="calculator">3.14 * 2 * 2 * 7</gadget>
<output>87.92</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">87.92 + 12.56</gadget>
<output>100.48</output>

<gadget id="calculator">100.48 * 2</gadget>
<output>200.96</output>

<result>200.96</result>