Sew together 24 of these 15 degree triangles to create a complete circle; 12 to create a half-circle; or 6 to create a quarter-circle. Create Fans, Dresden Plates, etc. up to a finished size of 48 inches. Total ruler length is 24.5". Use the vertical lines to fussy cut stripes or cut half triangles (the 1/4 inch seam allowance is marked). Or cut 30; 45; 60; and 90 degree units with the angles marked on the ruler.