The area of a triangle is 15dm**2, what is the area of a parallelogram with the same base and height as dm**2?
一个三角形的面积是15dm**2，和它等底等高的平行四边形的面积是多少dm**2．
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>