In a cylindrical water storage bucket, put a piece of round steel with a radius of 5 cm into the water, the water level will rise by 9 cm, and when the round steel is pulled out of the water for a length of 8 cm, the water level will drop by 6 cm. Find the surface area of the round bar.
在一个圆柱形储水桶里，把一段半径是5厘米的圆钢全部放入水中，水面就上升9厘米，把圆钢竖着拉出水面8厘米长后，水面就下降6厘米．求圆钢的表面积．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">78.5 * (2/3)</gadget>
<output>52.333333</output>

<gadget id="calculator">200 / 52.333333</gadget>
<output>3.821656</output>

<gadget id="calculator">3.14 * 3.821656</gadget>
<output>12</output>

<gadget id="calculator">3.14 * 5 * 2 * 12</gadget>
<output>376.8</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25 * 2</gadget>
<output>157</output>

<gadget id="calculator">376.8 + 157</gadget>
<output>533.8</output>

<result>533.8</result>