If the length and width of the rectangle are each increased by 10%, what is the increase in the area of the new rectangle compared to the area of the original rectangle?
长方形的长和宽各增加10%，那么新长方形面积比原长方形面积增加多少
<gadget id="calculator">21 / 100</gadget>
<output>21/100 = around 0.21</output>

<result>21/100 = around 0.21</result>