It is known that the area of the trapezoid is 45dm**2, the upper base is 4dm, and the lower base is 6dm. What is its height in dm?
已知梯形的面积是45dm**2，上底是4dm，下底是6dm，它的高是多少dm．
<gadget id="calculator">4 + 6</gadget>
<output>10</output>

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">45 * (1/5)</gadget>
<output>9</output>

<result>9</result>