Use a compass to draw a circle with a diameter of 15 cm. What is the distance between the two legs of the compass?
用圆规画一个直径是15厘米的圆，圆规两脚间叉开的距离是多少．
<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>