trapezoidal vegetable field has an upper bottom of 22m, a lower bottom of 28m, and a height of 15m. It can harvest 0.75kg of vegetables per square meter on average. How many kilograms of vegetables can be harvested in this vegetable field?
一块梯形菜地上底22m，下底28m，高15m，平均每平方米可收菜0.75kg，这块菜地可收菜多少千克？
<gadget id="calculator">22 + 28</gadget>
<output>50</output>

<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">50 * (15/2)</gadget>
<output>375</output>

<gadget id="calculator">0.75 * 375</gadget>
<output>281.25</output>

<result>281.25</result>