A bundle of 500 turns of wire, each 40 cm in diameter. How long is this bundle of wire?
一捆铁丝500圈，每圈直径40厘米．这捆铁丝长多少米？
<gadget id="calculator">500 / 100</gadget>
<output>5</output>

<gadget id="calculator">3.14 * 40 * 5</gadget>
<output>628</output>

<result>628</result>