If the area of a triangle is 10 square centimeters, what is the area of a parallelogram with the same base and height?
一个三角形的面积是10平方厘米，与它等底等高的平行四边形的面积是多少．
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>