Additionally

puts 'The circle is of radius ' + [(value1/3.14)/2].to_s + 'units'

Can be rewritten as

puts "The circle is of radius #{(value1/3.14)/2} units"

Converting things to a list just to be able to convert them to a string is
'code smell'. If you are calling the to_X methods all over the place you are
probably doing something wrong. Image someone pointing at you code and
saying "why did you do that?". If your answer is something like "dunno, it
works" then you have a problem.

Ruby code tends to be simpler and shorter than other languages. You will
often find yourself saying "what! is that it?"