If the circumference of a circle is increased by 30%, how much will the area of the circle increase?
一个圆的周长增加30%，那么这个圆的面积将增加多少．
<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 + (3/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">1 * (13/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">(13/10) ** 2</gadget>
<output>169/100 = around 1.69</output>

<gadget id="calculator">3.14 * (169/100)</gadget>
<output>5.3066</output>

<gadget id="calculator">5.3066 - 3.14</gadget>
<output>2.1666</output>

<gadget id="calculator">2.1666 / 3.14</gadget>
<output>0.69</output>

<result>0.69</result>