The upper base of the trapezoid is 24 cm, the lower base is 12 cm, and the height is 5 cm. What is the area in square centimeters?
梯形的上底是24厘米，下底是12厘米，高是5厘米，面积是多少平方厘米．
<gadget id="calculator">24 + 12</gadget>
<output>36</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">36 * (5/2)</gadget>
<output>90</output>

<result>90</result>