The side window glass of a car is a trapezoid with an upper base of 42 cm, a lower base of 58 cm, and a height of 30 cm. So what is the area of such a piece of glass in square centimeters?
一辆汽车的侧窗玻璃是一个梯形，上底42厘米，下底58厘米，高30厘米．那么这样的一块玻璃的面积是多少平方厘米？
<gadget id="calculator">42 + 58</gadget>
<output>100</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">100 * 15</gadget>
<output>1_500</output>

<result>1_500</result>