Draw the largest triangle in a rectangle with a length of 6 cm and a perimeter of 20 cm. What is the area of this triangle in square centimeters?
在一个长6厘米，周长是20厘米的长方形内画一个最大的三角形，这个三角形的面积是多少平方厘米？
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 - 6</gadget>
<output>4</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<result>12</result>