A trapezoidal paddy field has an upper base of 15m and a lower base of 25m. The area of the paddy field is 60㎡. Find the height of the paddy field.
一块梯形水田，上底是15m，下底是25m，水田的面积是60㎡，求水田的高．
<gadget id="calculator">15 + 25</gadget>
<output>40</output>

<gadget id="calculator">2 / 40</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">60 * (1/20)</gadget>
<output>3</output>

<result>3</result>