cylindrical tin bucket (without a lid) is 12 cm high and the diameter of the bottom is (3/4) high. About how many square decimeters of iron sheet is needed to make this bucket?
一个圆柱形铁皮水桶(无盖)，高12厘米，底面直径是高的(3/4)．做这个水桶大约要多少平方分米铁皮？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1.2 * (3/4)</gadget>
<output>0.9</output>

<gadget id="calculator">0.9 / 2</gadget>
<output>0.45</output>

<gadget id="calculator">0.45 ** 2</gadget>
<output>0.2025</output>

<gadget id="calculator">3.14 * 0.2025</gadget>
<output>0.63585</output>

<gadget id="calculator">3.14 * 0.9 * 1.2</gadget>
<output>3.3912</output>

<gadget id="calculator">0.63585 + 3.3912</gadget>
<output>4.02705</output>

<result>4.02705</result>