a rectangle is 6in wide and 14in tall if it is reduced to a width of 3in then how tall will it be
I am assuming that you want to reduce the height proportionally to reducing the width.
You made the width 1/2 as big when you took it from 6" to 3 ". You divided 6 by 2 to get 3.
What do you think you should do to the 14"?