A rope can wrap 5.5 times around a tree pole with a diameter of 4 decimeters. How long is the rope in decimeters?
一根绳子能绕直径是4分米的树杆5.5圈，这根绳子长多少分米．
<gadget id="calculator">3.14 * 4 * 5.5</gadget>
<output>69.08</output>

<result>69.08</result>