The sum of the upper and lower bases of the trapezoid is 50 decimeters, and the height is 6 decimeters. What is the area in square decimeters?
梯形的上下两底的和是50分米，高是6分米，面积是多少平方分米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">50 * 3</gadget>
<output>150</output>

<result>150</result>