7800÷3=2600
1(largest building)
[tex]2600 + 300 + 900 = 3800[/tex]
2(2nd largest building)
[tex]2600 - 300 = 2300[/tex]
3(smallest building)
[tex]2600 - 900 = 1700[/tex]
If you want to double check if these are the correct answers this is the equation:
[tex]3800 + 2300 + 1700 = 7800[/tex]
plz mark brainiest