What is the area of a right triangle whose two sides are 90 decimeters and 12 decimeters respectively?
一个直角三角形，两条直角边分别是90分米和12分米，它的面积是多少平方分米．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">90 * 6</gadget>
<output>540</output>

<result>540</result>