A trapezoidal piece of land has an upper base of 4.5 meters, a lower base of 7.5 meters, and a height of 10 meters. If trees are planted on this piece of land, and each tree covers an area of 1.5 square meters, how many trees can be planted on this piece of land?
一块梯形的土地，上底4.5米，下底7.5米，高10米．如果在这块土地上植树，每棵树占地1.5平方米，这块地一共能植多少棵树？
<gadget id="calculator">4.5 + 7.5</gadget>
<output>12</output>

<gadget id="calculator">10 / 2 / 1.5</gadget>
<output>3.333333</output>

<gadget id="calculator">12 * 3.333333</gadget>
<output>39.999996</output>

<result>39.999996</result>