A rectangular iron sheet, 10 decimeters long and 8 decimeters wide, can be cut along its diagonal to form two triangles of equal size. What is the area of each triangle?
一块长方形铁皮，长10分米，宽8分米，沿它的对角线裁开，可裁成2个大小相等的三角形，每个三角形的面积是多少平方分米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>