If the radius of a circle increases from 5 cm to 10 cm, the area of the circle increases by how many square centimeters.
一个圆的半径由5厘米增加到10厘米，圆的面积增加了多少平方厘米．
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">314 - 78.5</gadget>
<output>235.5</output>

<result>235.5</result>