The sum of the upper and lower bases of a trapezoid is 15 meters and the height is 3 meters. What is its area m**2.
一个梯形上底和下底的和是15米，高3米，它的面积是多少m**2．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">15 * (3/2)</gadget>
<output>45/2 = around 22.5</output>

<result>45/2 = around 22.5</result>