Working out your surface area can be useful when planning aquascapes or working out volume.
Technically, these formulas are just working out 'area', but for aquatic purposes we can call it 'surface area'.
Surface area | RectangleArea = (AxB)
Surface area | CircleArea = (Pi Π x r2)
Surface area | TriangleArea = (AxB)/2
Surface area | HexagonArea = (AxB) x0.5 x6
Surface area | OctagonArea = (AxB) x0.5 x8
Surface area | TrapezoidArea = C/2 x (A+B)
Volume from surface areaAssuming straight sides and the same depth through the tank, you can easily work out the volume of your tank by multiplying the surface area by the height and dividing by 1000: