Use a 19-meter-long rope to measure the circumference of a round table. If there is a difference of 78.2 cm, you can go around 7 times. Find the diameter of the round table.
用一根长是19米的绳子来测量一个圆形桌子的周长，还差78.2厘米就可以绕了7圈了，求这张圆桌子的直径．
<gadget id="calculator">78.2 / 100</gadget>
<output>0.782</output>

<gadget id="calculator">19 + 0.782</gadget>
<output>19.782</output>

<gadget id="calculator">19.782 / 7 / 3.14</gadget>
<output>0.9</output>

<result>0.9</result>