A trapezoidal decorative panel has an upper base of 8dm, a lower base of 10dm, and a height of 2dm. Both sides must be painted. What is the painted area?
一个梯形装饰板，上底8dm，下底10dm，高2dm，两面都要涂油漆，涂油漆的面积是多少．
<gadget id="calculator">8 + 10</gadget>
<output>18</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">18 * 1 * 2</gadget>
<output>36</output>

<result>36</result>