Galvanize the inner and outer surfaces of a water pipe with a length of 50 cm, an inner diameter of 6 cm, and an outer diameter of 8 cm. What is the galvanized area?
将一根长50厘米，内直径6厘米，外直径8厘米的水管内外表面镀锌，求镀锌的面积是多少？
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">16 - 9</gadget>
<output>7</output>

<gadget id="calculator">3.14 * 7 * 2</gadget>
<output>43.96</output>

<gadget id="calculator">3.14 * 6 * 50</gadget>
<output>942</output>

<gadget id="calculator">3.14 * 8 * 50</gadget>
<output>1_256</output>

<gadget id="calculator">43.96 + 942 + 1_256</gadget>
<output>2_241.96</output>

<result>2_241.96</result>