Radius = Circumfrence/2*π
Begin by measuring your widest area (hips and butt) that number will be your circumference. Mine was 37 inches. So... 37/2*π (π = 3.14). I rounded the number up to 6 inches. That is the first radius measurement you'll need.We'll call it Hip Radius
Step 1 Cutting out Fabric:
Fold your fabric into fourths. (fold hotdog, then hamburger) Your folds will be on the left and on the top, Starting in the top left corner (where all the folds meet) mark your hip radius multiple times. Connect the marks so you have a quarter circle.
Next decide how long you want your first tier to be. I decided on 6 inches. I added 1 inch for seem allowances. Add your length measurement to you hip radius measurement 6 + 7 = 13 inches. Starting again in the top left corner mark your hip + length radius multiple times. Connect the marks to make a bigger quarter circle.
Cut out on the lines you just created. It will look like a donut.
Diagram of measurements.
Next you will need to cut out the fabric for your other 2 tiers. Math time again... you will need to know the measurement of the outer circumference of your skirt.