A sector has a radius of 2 decimeters and an arc length of 7 decimeters, what is the area of the sector in square decimeters?
一个扇形半径为2分米，弧长7分米，这个扇形的面积是多少平方分米．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 7 * 2</gadget>
<output>7</output>

<result>7</result>