If the perimeter of a parallelogram is 30 meters and one side is 8 meters long, what is the length of its adjacent side?
一个平行四边形的周长是30米，其中一条边长8米，它的邻边长多少米？
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">15 - 8</gadget>
<output>7</output>

<result>7</result>