parallelogram and a triangle have the same base and height. Given that the area of the parallelogram is 30 square centimeters, what is the area of the triangle?
一个平行四边形和一个三角形等底等高．已知平行四边形的面积是30平方厘米，三角形的面积是多少？
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<result>15</result>