The area of an isosceles trapezoid is 18cm**2, the height is 4cm, and the length of one side is 5cm. What is the perimeter of this isosceles trapezoid in cm?
一个等腰梯形的面积是18cm**2，高是4cm，一条腰长5cm，那么这个等腰梯形的周长是多少cm．
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">18 * (1/2)</gadget>
<output>9</output>

<gadget id="calculator">9 + 5 + 5</gadget>
<output>19</output>

<result>19</result>