The sum of the two sides of an isosceles triangle is 8.4 decimeters, what is its area in square decimeters?
一个等腰三角形的两条直角边的和是8.4分米，它的面积是多少平方分米．
<gadget id="calculator">8.4 / 2</gadget>
<output>4.2</output>

<gadget id="calculator">4.2 / 2</gadget>
<output>2.1</output>

<gadget id="calculator">4.2 * 2.1</gadget>
<output>8.82</output>

<result>8.82</result>