The length of a rectangle is 35 decimeters, the width is 12 decimeters, and the height of a parallelogram equal to its area is 21 decimeters. What is the base corresponding to this height?
一个长方形的长是35分米，宽是12分米，与它面积相等的平行四边形的高是21分米，则这条高所对应的底是多少分米．
<gadget id="calculator">12 / 21</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">35 * (4/7)</gadget>
<output>20</output>

<result>20</result>