An isosceles trapezoid has an upper base of 6 decimeters, a lower base of 9 decimeters, and a waist of 5 decimeters. What is the perimeter of this trapezoid?
一个等腰梯形，上底长6分米，下底长9分米，腰长5分米，这个梯形的周长是多少分米．
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">6 + 9 + 10</gadget>
<output>25</output>

<result>25</result>