SOLUTION: Completely simplify and rationalize the denominator: (√160) / (√250) * (√245) / (√108)

The starting number is 

    .


To simplify writing, consider two factors separately,    and  .


First factor    is the same as  .


In the last expression, reduce the common factor of 10 in the numerator and denominator under the square root, 
so you have

     =  =  = .    (1)


Second factor    is the same as  .


In the last expression, transform

     =  = .    (2)


From (1) and (2), you have 

     =  =  = .    (3)


Now rationalize expression (3) multiplying it by  

     =  =  = .


At this point, the job is complete.


ANSWER.   = .