If the base and height of a parallelogram are both increased by 10%, what is the increase in the area of the parallelogram?
一个平行四边形的底和高都增加10%，则这个平行四边形的面积增加多少
<gadget id="calculator">1.21 - 1</gadget>
<output>0.21</output>

<result>0.21</result>