triangle and a parallelogram have the same base and the same height. The area of the triangle is 15 square centimeters. What is the area of the parallelogram in square centimeters?
一个三角形和一个平行四边形的底相等，高也相等，三角形的面积是15平方厘米，平行四边形的面积是多少平方厘米．
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>