<human>:  A company was contracted to construct three buildings, with the second building being two times as tall as the first building. The third building had to be three times as tall as the combined height of the first and second buildings. If the first building was 600 feet, calculate the total height of the three buildings together.
<bot>: How tall is the second building? ** The second building is two times as tall as the first building, a total of 600*2 = <<600*2=1200>>1200 feet.
How tall is the first and second building together? ** The total height of the first and the second building is 1200+600 = <<1200+600=1800>>1800 feet.
How tall is the third building? ** The third building is three times as tall as the combined height of the first and second buildings, which is 1800*3 = <<1800*3=5400>>5400 feet.
How tall are the three buildings together? ** Together, the three buildings have a total height of 5400+1800 = <<5400+1800=7200>>7200 feet.
#### 7200