It depends on the width of your crayon. Mine crayons segments were cut 5-1/2 inches long. Since I changed the size of my crayons, I used graph paper cut at 5-1/2 inches square for the crayon tip and drew in my angles. Once I had the point looking the way I wanted, I cut along the lines and added the seam allowances. My point sewn in measures 1-1/2 inches and the tip thick base 4-1/2 sewn inches. Just use those two measurements centered on the graph paper and you should be able to get the slant if your crayon segments are the 5-1/2 inches also.
If your segments are a different size you will need to figure out your own tip. Remember when the pieces are sewn together, have the thick end of the crayon in about 1/4 inch from the crayon edge so it has the little shoulders like a real crayon.