If the radius of a circle is increased by 50%, its area will increase by as much.
圆的半径增加50%，它的面积就增加多少．
<gadget id="calculator">3.14 * 1 * 1</gadget>
<output>3.14</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) ** 2</gadget>
<output>9/4 = around 2.25</output>

<gadget id="calculator">3.14 * (9/4)</gadget>
<output>7.065</output>

<gadget id="calculator">7.065 - 3.14</gadget>
<output>3.925</output>

<gadget id="calculator">3.925 / 3.14</gadget>
<output>1.25</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">1.25 * 1</gadget>
<output>1.25</output>

<result>1.25</result>