A rectangle has a perimeter of 90 cm and the ratio of length to width is 2:7. What is the area of this rectangle?
一长方形，周长为90厘米，长和宽的比是2：7，这个长方形的面积是多少？
<gadget id="calculator">7 + 2</gadget>
<output>9</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">90 * (7/9)</gadget>
<output>70</output>

<gadget id="calculator">70 / 2</gadget>
<output>35</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">90 * (2/9)</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">35 * 10</gadget>
<output>350</output>

<result>350</result>