The upper base of a trapezoid is 2.4dm, shorter than the lower base by 2.6dm, and the height is 4dm. If it is made into a parallelogram, a triangle of dm**2 must be added.
一个梯形的上底是2.4dm，比下底短2.6dm，高是4dm，如果把它补成一个平行四边形，需补上一个多少dm**2的三角形．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2.6 * 2</gadget>
<output>5.2</output>

<result>5.2</result>