The outer diameter of the bottom of a barrel is 3.2 decimeters. Add an iron hoop to it. The joint of the iron hoop is 0.2 decimeters. How long is the iron hoop?
一只桶底的外直径是3.2分米，给它加上一道铁箍，铁箍的接头处有0.2分米，这道铁箍长多少分米．
<gadget id="calculator">3.14 * 3.2</gadget>
<output>10.048</output>

<gadget id="calculator">10.048 + 0.2</gadget>
<output>10.248</output>

<result>10.248</result>