6.021 m/second
825m equals 0.825km
1km = 1000m 825m x 1km/1000m = 0.825km
825m = 0.825 km 0.51263123 miles
3000 meters are in 3km 1000 meters per km .
I personally think the answer to this question comes down to a matter of opinion. I think really it depends on what kind of building you think about, see a tall house would be around 3 stories high or around 25 metres, however an office building that was 3 stories or 25 metres high would seem fairly small. You would also have to consider the context of the period you would be describing the building. In early 1905 the Met Life Tower in New York City was the tallest building in the world standing at 213m, however, currently the tallest building in the world is the Burj in Dubai, standing at 825m - interpretation of 'tall' will change rapidly over time. Furthermore, consideration of 'tall' should be to which country you would be in. Countries less economically developed would perhaps see fewer tall buildings so their peoples interpretation of 'tall' would be different, whereas those living in NY City would be accustomed to skyscrapers and may not consider them 'tall'. Personally, i think a tall building would have a height of 50 metres. But that's just me.