A semicircular aquarium has a radius of 5 meters, what is the perimeter of the aquarium in meters?
一个半圆形养鱼池，半径是5米，这个养鱼池的周长是多少米？
<gadget id="calculator">3.14 * 5</gadget>
<output>15.7</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">15.7 + 10</gadget>
<output>25.7</output>

<result>25.7</result>