If the base of a parallelogram is 7 cm and the height is 4 cm, what is its area in square centimeters?
一个平行四边形的底是7厘米，高是4厘米，它的面积是多少平方厘米．
<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<result>28</result>