Hi Math help Forum

I'm not sure if this is the right thread to be posting this in, so sorry.

the question is to calculate |a x b| where

a= i+j-k

b=2i-j+3k

I've worked out a x b to be 2i - 5j - 3k , but I'm not really sure as to where to go from here.

any help would be great

Thanks

ES