If the perimeter of a square is 6.4 cm, what is the area of a triangle whose base and height are equal to the sides of the square?
一个正方形周长是6.4cm，底和高都与正方形的边长相等的三角形的面积是多少．
<gadget id="calculator">6.4 / 4</gadget>
<output>1.6</output>

<gadget id="calculator">1.6 / 2</gadget>
<output>0.8</output>

<gadget id="calculator">1.6 * 0.8</gadget>
<output>1.28</output>

<result>1.28</result>