find out/figure out/sort out/make out/work out why

[joham]

We have to find out/figure out/sort out/make out/work out why earthquakes happen.

Can all five be used in this sentence, meaning 'find the answer to' or 'discover'?

Thank you in advance.

 

[SlickVic9000]

(Not a Teacher)

They all could work. "Figure out" and "find out" work the best in this context.

 

[emsr2d2]

We have to find out/figure out/sort out/make out/work out why earthquakes happen.

Can all five be used in this sentence, meaning 'find the answer to' or 'discover'?

Thank you in advance.

The only one I don't like if you want it to mean "discover" is "sort out". The rest mean the same, more or less.