The circumference of a circle is 15.7m, what is its radius in dm
一个圆的周长是15.7m，它的半径是多少dm
<gadget id="calculator">15.7 / 3.14 / 2</gadget>
<output>2.5</output>

<gadget id="calculator">2.5 * 10</gadget>
<output>25</output>

<result>25</result>