Hi!
You did not mention what type of prairie points you had in mind to make.
Here is a tute for making a continuous prairie points...and the fabric is 4 X the height of the prairie point and the length of your quilt sides. This is probably the easiest method. You can also use two different fabrics, cut each 2 X the height of your prairie point and add 1/4" to each width for the seam allowance, sew them right sides together and follow the rest of the tute.
http://patchworkunderground.com/blog...oints-tutorial