A cylindrical cake box has a bottom radius of 30 cm and a height of 20 cm. It is tied with a ribbon and the joint is 10 cm. How many centimeters of ribbon is needed?
一个圆柱形蛋糕盒底面半径是30厘米，高是20厘米，用丝带捆扎，接头处是10厘米，需要多少厘米丝带绳．
<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<gadget id="calculator">60 * 4</gadget>
<output>240</output>

<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">240 + 80 + 10</gadget>
<output>330</output>

<result>330</result>