The shape of a fish pond is trapezoidal, its upper base is 21 meters long, its lower base is 45 meters long, and its area is 759 square meters. How tall is it?
一个鱼塘的形状是梯形，它的上底长21米，下底长45米，面积是759平方米．它的高是多少？
<gadget id="calculator">21 + 45</gadget>
<output>66</output>

<gadget id="calculator">2 / 66</gadget>
<output>1/33 = around 0.030303</output>

<gadget id="calculator">759 * (1/33)</gadget>
<output>23</output>

<result>23</result>