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

<result>30</result>