An object falls from the top of a tall building and falls to the ground after 3 seconds. It is known that the fall is 4.9 meters in the first second, and the fall is 9.8 meters more in each second than the previous second. How many meters is the height of this building?
一个物体从一座高楼楼顶坠落，经过3秒落地．已知第一秒下落4.9米，以后每一秒都比前一秒多下落9.8米，这座楼房高多少米．
<gadget id="calculator">4.9 + 9.8</gadget>
<output>14.7</output>

<gadget id="calculator">9.8 * 2</gadget>
<output>19.6</output>

<gadget id="calculator">4.9 + 19.6</gadget>
<output>24.5</output>

<gadget id="calculator">4.9 + 14.7 + 24.5</gadget>
<output>44.1</output>

<result>44.1</result>