Zhang Hong's house has a circular pool with a radius of 5.3 meters. How many meters does it take to walk around the pool twice?
张红家有一个半径是5.3米的圆形水池，绕这个水池走两圈，要走多少米．
<gadget id="calculator">2 * 3.14 * 5.3 * 2</gadget>
<output>66.568</output>

<result>66.568</result>