There are three natural numbers a, b, and c. It is known that a*b=30, b*c=35, and c*a=42. Then, what should be the value of a*b*c?
有三个自然数a、b、c，已知a*b=30，b*c=35，c*a=42，那么，计算a*b*c的值应该是多少
<gadget id="calculator">30 / 5</gadget>
<output>6</output>

<gadget id="calculator">35 / 5</gadget>
<output>7</output>

<gadget id="calculator">6 * 5 * 7</gadget>
<output>210</output>

<result>210</result>