A cylindrical cake box has a bottom radius of 3 decimeters and a height of 1.5 decimeters. How many square decimeters of hard paper are needed to make such a cake box?
一个圆柱形蛋糕盒，底面半径是3分米，高是1.5分米，做这样一个蛋糕盒至少需要硬纸多少平方分米？
<gadget id="calculator">3.14 * 3 * 2 * 1.5</gadget>
<output>28.26</output>

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

<gadget id="calculator">3.14 * 9 * 2</gadget>
<output>56.52</output>

<gadget id="calculator">28.26 + 56.52</gadget>
<output>84.78</output>

<result>84.78</result>