First use a compass to draw a circle with a circumference of 15.7 cm, and then draw a largest square inside this circle. What is the area of this square in square centimeters?
先用圆规画一个周长是15.7厘米的圆形，然后在这个圆内再画一个最大的正方形，这个正方形的面积是多少平方厘米．
<gadget id="calculator">15.7 / 3.14 / 2</gadget>
<output>2.5</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">2.5 * (5/2)</gadget>
<output>6.25</output>

<gadget id="calculator">6.25 * 2</gadget>
<output>12.5</output>

<result>12.5</result>