A 9 cm, 7 cm wide, 3 cm high cuboid iron block and a 5 cm square iron block are melted and cast into a cylinder with a bottom diameter of 20 cm. Rust paint, how many square centimeters is the painted area?
把一个9厘米，宽7厘米，高3厘米的长方体铁块和一个棱长为5厘米的正方体铁块，熔铸成一个底面直径为20厘米的圆柱，为了防锈蚀，要在其表面刷上防锈漆，求刷漆的面积是多少平方厘米？
<gadget id="calculator">9 * 7 * 3</gadget>
<output>189</output>

<gadget id="calculator">5 * 5 * 5</gadget>
<output>125</output>

<gadget id="calculator">189 + 125</gadget>
<output>314</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">314 / 314</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 20 * 1</gadget>
<output>62.8</output>

<gadget id="calculator">3.14 * 100 * 2</gadget>
<output>628</output>

<gadget id="calculator">62.8 + 628</gadget>
<output>690.8</output>

<result>690.8</result>