A quadrilateral is formed by 4 wooden sticks each 5 decimeters in length. What is the perimeter of the quadrilateral in decimeters?
用4根长都是5分米的木棒围成一个四边形，这个四边形的周长是多少分米．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>