Step 4: Determine how many ticks you need to either go up from the lower percentile or go down from the upper percentile. In our case, we want to find the 75th percentile which is 5 percentiles or ticks below the 80th.

Step 5: Since we now know that each tick is worth 0.05 (from Step 3) and we know that we want the score that is 5 ticks below 80 (from Step 4), we can estimate our 75th percentile by creating the following chart (below Step 5):