Sew together 16 of these 22-1/2 degree triangles to create a complete circle; 8 to create a half-circle; or 4 to create a quarter-circle. Create Fans, Dresden Plates, etc. up to a finished size of 36 inches. Total ruler length is 18-1/2 inches. Use the vertical line to fussy cut stripes or cut half triangles (the 1/4 inch seam allowance is marked). Or use the angled lines to create intricate blocks as instructed in companion patterns.