If the base of a parallelogram is 4.2 cm and the height is 1.5 cm, what is the area of the triangle with the same base and height in square centimeters?
一个平行四边形图片的底是4.2厘米，高是1.5厘米，和它等底等高的三角形的面积是多少平方厘米．
<gadget id="calculator">1.5 / 2</gadget>
<output>0.75</output>

<gadget id="calculator">4.2 * 0.75</gadget>
<output>3.15</output>

<result>3.15</result>