The sum of the upper and lower bases of a trapezoid is 45 cm and the height is 10 cm. What is the area of the trapezoid in square centimeters?
一个梯形，上底与下底的和是45厘米，高是10厘米，这个梯形的面积是多少平方厘米．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">45 * 5</gadget>
<output>225</output>

<result>225</result>