If the lengths of the three sides of a right triangle are 3 cm, 4 cm, and 5 cm, what is its area in square millimeters?
一个直角三角形三条边的长分别为3厘米、4厘米、5厘米，它的面积是多少平方毫米．
<gadget id="calculator">6 * 100</gadget>
<output>600</output>

<result>600</result>