A rectangular playground has a perimeter of 280 meters and a ratio of length to width of 4:3. What is the area of the playground in square meters?
一个长方形的操场，周长是280米，长与宽的比是4：3，这个操场的面积是多少平方米．
<gadget id="calculator">280 / 2</gadget>
<output>140</output>

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">140 * (4/7)</gadget>
<output>80</output>

<gadget id="calculator">80 * 70</gadget>
<output>5_600</output>

<result>5_600</result>