The landscape architect wanted to plant some magnolia trees in a trapezoidal open space with an upper base of 4.8m, a lower base of 7.2m, and a height of 8m for greening. If each tree occupies an area of 1m**2, how many magnolias can be planted in this open space?
园林师想在一块上底是4.8m，下底是7.2m，高是8m的梯形空地栽上一些白玉兰树进行绿化．如果每棵树占地1m**2，这块空地可以栽多少棵白玉兰？
<gadget id="calculator">4.8 + 7.2</gadget>
<output>12</output>

<gadget id="calculator">8 / 2 / 1</gadget>
<output>4</output>

<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<result>48</result>