The perimeter of an isosceles trapezoid is 74 cm, the waist length is 15 cm, and the height is 9 cm. Find the area of the trapezoid.
一个等腰梯形的周长是74厘米，腰长15厘米，高9厘米，求梯形的面积．
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">74 - 30</gadget>
<output>44</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">44 * (9/2)</gadget>
<output>198</output>

<result>198</result>