Plant trees around a circular pool with a diameter of 8 meters, and plant one tree every 1.57 meters. How many trees are planted in total?
在直径是8米的圆形水池周围栽树，每隔1.57米栽一棵，共栽多少棵．
<gadget id="calculator">8 / 1.57</gadget>
<output>5.095541</output>

<gadget id="calculator">3.14 * 5.095541</gadget>
<output>15.999999</output>

<result>15.999999</result>