The sum of the upper and lower bases of a trapezoid is 4.2m, and the height is 1.2m. What is its area?
一个梯形的上底与下底的和是4.2m，高是1.2m，它的面积是多少．
<gadget id="calculator">1.2 / 2</gadget>
<output>0.6</output>

<gadget id="calculator">4.2 * 0.6</gadget>
<output>2.52</output>

<result>2.52</result>