We need the perimeter of the window for framing
The window is in the shape of a rectangle with the height of
feet and width of 
. The diagram of the shape is shown below
The perimeter of a shape is obtained by adding up the length of all the sides that form the shape.
The perimeter of the window is
= 
We have two whole numbers 18 and 12 and two fractions
and 
Adding the two fractions that have different denominator
, which is an improper fraction which we can change into a mixed number 
So the perimeter of the window is
and the length of wood needed for the frame is
feet
The window is in the shape of a rectangle with the height of
The perimeter of a shape is obtained by adding up the length of all the sides that form the shape.
The perimeter of the window is
We have two whole numbers 18 and 12 and two fractions
Adding the two fractions that have different denominator
So the perimeter of the window is
and the length of wood needed for the frame is