Breaking down my 180 Gallon Tank

[Ticketyboo]

Hi all, after a few enquiries about my tank, here are the dimensions of the tank so solve any confusions;

72 inch long by 18 inches deep and 24 inches high , so if this does not make it a 180 gallon as i thought it was when i purchased it, im not sure of the exact holding.

Thanks

EDIT: The Wifey tells me the dimensions are 72 x 30 x 18 = 180 gal