i had the most difficult question given to me the other day and i still dont know how to do it!

the question read

in the following formulae transpose to make the given variable the subject of the formula.

A. stress= load divided area for area

find out its valu when stress = 125KN/m2 and load = 213.5KN to 1 decimal place.

could someone please show me the steps into how to work this out!!!