you know how you divide the centre angle by 360 to get the sector area on a circle? what if they don't give you an angle, what do i do then?
If they are only giving you a portion of the crcle.......you can use (portion) * pi ^ radius^2
For.....example.......find the area of (1/6) of a circle with a radius of 5 ......so we have...
Area = (1/6) * pi * (5)^2 ≈ 13.1 square units
I don't know if this is what you needed, or not......