We will use a few different sizes to give you a better idea
DO NOT FORGET DECIMAL POINTS, OK.
Otherwise your window could turn out to be over
1 million dollars.
For round windows,you measure an imaginary square
over the area of the window and then follow the normal
proceedures below.
EG:1  Window panel quote

IN THIS QUOTE YOUR MATHEMATICS WOULD READ
#First times the length by the height so .600 X .300( note the decimals)
#Then divide by  .09 ,so far it would look like .600 x .300 divided by .09
#Then time that by 70 ,so in effect your whole sum should read
.600 x .300 divide by .09 then x 70 ..the answer is then always in dollars
so therefore the answer is 140 so that means it would cost $140 for a
 window 600mm x 300 mm (1ft x 2ft )

EG2:MEDIUM WINDOW QUOTE

THE MATHEMATIC EQUATION FOR THIS WINDOW WOULD BE

1.100 X .325 divided by .09 then times by 70 =278.05 so therefore it is
  $278.05 for a window of this size.
If you cannot work out your window price ,you can always email me with the measurementsand and I can email you what it would costs
FITTING IS EXTRA BUT IS USUALLY LESS THAN $40.
 email your measurements