If the perimeter of a rectangle is 38 cm and the width is 9 cm, what is the area in square centimetres?
一个长方形的周长是38cm，宽是9cm，面积是多少平方厘米．
<gadget id="calculator">38 / 2</gadget>
<output>19</output>

<gadget id="calculator">19 - 9</gadget>
<output>10</output>

<gadget id="calculator">10 * 9</gadget>
<output>90</output>

<result>90</result>