A belt drives two wheels. The diameter of the big wheel is 30 cm, and the diameter of the small wheel is 10 cm. The small wheel turns 300 times per minute. How many times does the big wheel turn per minute? (Solution by solution of proportion)
一根皮带带动两个轮子，大轮直径30厘米，小轮直径10厘米，小轮每分转300圈，大轮每分转几圈？(用解比例的方法解)
<gadget id="calculator">3.14 * 10 * 300</gadget>
<output>9_420</output>

<gadget id="calculator">3.14 * 30</gadget>
<output>94.2</output>

<gadget id="calculator">9_420 / 94.2</gadget>
<output>100</output>

<result>100</result>