On a 100:1 drawing, the diameter of a circular part is measured as 2 cm. What is the actual area of the circular part in square centimeters (reserve π in the result).
在一个100：1的图纸上，量得一个圆形零件的直径为2厘米，这个圆形零件的实际面积是多少平方厘米(结果中保留π)．
<gadget id="calculator">100 / 1</gadget>
<output>100</output>

<gadget id="calculator">2 / 100</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/50) / 2</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">(1/100) ** 2</gadget>
<output>1/10_000 = around 0.0001</output>

<result>1/10_000 = around 0.0001</result>