There is a piece of trapezoidal paper with an upper base of 7 cm, a lower base of 12 cm, and a height of 8 cm. Now one side of this paper is to be painted red. What is the area of the painted part in square centimeters?
有一块上底是7厘米，下底是12厘米，高是8厘米的梯形纸片，现在要把这张纸的一面涂上红色，涂色部分的面积是多少平方厘米．
<gadget id="calculator">7 + 12</gadget>
<output>19</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">19 * 4</gadget>
<output>76</output>

<result>76</result>