Cut out the largest triangle from a trapezoidal piece of paper with an upper base of 5 cm, a lower base of 8 cm, and a height of 6 cm. What is the area of this triangle in square centimetres.
从一个上底是5厘米，下底是8厘米，高是6厘米的梯形纸片上剪下一个最大的三角形．这个三角形的面积是多少平方厘米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<result>24</result>