Help measuring for a light?

[Jayson Ledbetter]

i have a 5 sided 45 gallon corner tank, how do I measure this for the correct light strip size? Thanks in advance

 

[CoralManz]

What do you plan to keep in there?

 

[Jayson Ledbetter]

55-60 pounds of live rock, easier kept corals and a couple smaller fish. I have no idea how to measure the top of the tank since it's 5 sided. The longest point is 30" across,

 

[CoralManz]

I would go with a light source with enough spread to cover it if it were a cube.