A right-angled trapezoidal vegetable field with an area of 78 square meters is enclosed by a fence against a wall, and the height of the vegetable field is 12 meters. How many meters of fences are needed to enclose such a vegetable field?
用篱笆靠墙围成一个面积是78平方米的直角梯形菜地，菜地的高是12米．围成这样一个菜地共需要多少米的篱笆？
<gadget id="calculator">2 / 12</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">78 * (1/6)</gadget>
<output>13</output>

<gadget id="calculator">13 + 12</gadget>
<output>25</output>

<result>25</result>