I have a large 60* triangle and I laid two long rulers along the edges to see how much fabric you would need. To cut a triangle that will be 23" from the center of the base to the center of the point (which will give you the 45" diameter), you will need 27-28" of fabric. Each side will be 27-28" long. Those 6 triangles will be huge! I think maybe you want to invest in a 60* triangle to make cutting this easier, It doesn't have to be real big, because the angle will just extend out farther, the taller the triangle gets. Hope this helps.