A right-angled triangle vegetable field, the three side lengths are 30 meters, 40 meters, 50 meters respectively, what is the area of this vegetable field in square meters
一块直角三角形菜地，三条边长分别是30米、40米、50米，这块菜地的面积是多少平方米
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">30 * 20</gadget>
<output>600</output>

<result>600</result>