A rectangular swimming pool with a circumference of 90 meters has a ratio of length to width of 5:4. How many square meters does this rectangular swimming pool occupy?
一块周长90米的长方形游泳池，它的长和宽的比是5：4．这个长方形游泳池的占地面积是多少平方米？
<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">45 * (5/9)</gadget>
<output>25</output>

<gadget id="calculator">45 - 25</gadget>
<output>20</output>

<gadget id="calculator">25 * 20</gadget>
<output>500</output>

<result>500</result>