The upper base of a trapezoid is 9 decimeters, the lower base is 15 decimeters, and the height is 6 decimeters. Draw the largest triangle in this trapezoid. What is the area of this triangle in square decimeters?
一个梯形的上底是9分米，下底是15分米，高是6分米，在这个梯形里面画一个最大的三角形，这个三角形的面积是多少平方分米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">15 * 3</gadget>
<output>45</output>

<result>45</result>