The right angle side of an isosceles right triangle is 4 decimeters, what is the area of this triangle?
一个等腰直角三角形的直角边是4分米，这个三角形的面积是多少．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>