The farm has a trapezoidal vegetable field with an area of 4896 square meters. The upper base is 79.8 meters high and the height is 60 meters. How many meters is the lower base of this vegetable field? (solution by equation)
农场有一块面积是4896平方米的梯形菜地，上底是79.8米，高60米，这块菜地的下底是多少米？(用方程解)
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">79.8 * 30</gadget>
<output>2_394</output>

<gadget id="calculator">4_896 - 2_394</gadget>
<output>2_502</output>

<gadget id="calculator">2_502 / 30</gadget>
<output>417/5 = around 83.4</output>

<result>417/5 = around 83.4</result>