An isosceles trapezoid has an upper base of 4 cm, a lower base of 6 cm, and a waist of 5 cm. What is the perimeter of the trapezoid in cm?
一个等腰梯形，它的上底长是4厘米，下底长是6厘米，一腰的长是5厘米，这个梯形的周长是多少厘米．
<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">4 + 6 + 10</gadget>
<output>20</output>

<result>20</result>