What is the area of an isosceles right triangle whose longest side is 20 cm?
一块等腰直角三角板，最长边为20厘米，它的面积是多少平方厘米．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>