Uncle Zhang wants to make an uncovered cylindrical iron bucket with a bottom diameter of 3 decimeters and a height of 4.5 decimeters. How many square decimeters of iron is needed at least?
张叔叔要做一个底面直径3分米，高4.5分米的无盖圆柱形铁皮水桶，至少需要铁皮多少平方分米？
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) ** 2</gadget>
<output>9/4 = around 2.25</output>

<gadget id="calculator">3.14 * (9/4)</gadget>
<output>7.065</output>

<gadget id="calculator">3.14 * 3 * 4.5</gadget>
<output>42.39</output>

<gadget id="calculator">7.065 + 42.39</gadget>
<output>49.455</output>

<result>49.455</result>