The upper base of a trapezoidal hillside is 280 meters, the lower base is 540 meters, and the height is 160 meters. What is the area of this hillside?
一块梯形山坡地的上底是280米，下底是540米，高是160米，这块山坡地的面积是多少公顷？
<gadget id="calculator">280 + 540</gadget>
<output>820</output>

<gadget id="calculator">160 / 2 / 10_000</gadget>
<output>1/125 = around 0.008</output>

<gadget id="calculator">820 * (1/125)</gadget>
<output>164/25 = around 6.56</output>

<result>164/25 = around 6.56</result>