The area of an equal quadrilateral formed by two identical trapezoids is 45 square centimeters, the height of the trapezoid is 5 centimeters, and the sum of the upper and lower bases in centimeters.
由两个完全一样的梯形拼成的平等四边形的面积是45平方厘米，梯形的高是5厘米，上下底的和多少厘米．
<gadget id="calculator">45 / 2</gadget>
<output>45/2 = around 22.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(45/2) * (2/5)</gadget>
<output>9</output>

<result>9</result>