wire is wound 10 times around a cylindrical steel pipe. The outer diameter of the steel pipe is 15 cm long. What is the length of the wire in cm?
一根铁丝在圆柱形钢管上绕了10圈，钢管的外直径长15厘米，这根铁丝长多少厘米．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">3.14 * 15 * (1/10)</gadget>
<output>4.71</output>

<result>4.71</result>