What is the increase in circumference of a circle with a radius of 1.5 decimeters divided equally along its diameter in half?
把一个半径为1.5分米的圆沿直径平均分成两半后周长增加了多少分米．
<gadget id="calculator">1.5 * 2 * 2</gadget>
<output>6</output>

<result>6</result>