I just use the cross multiple rule. X/X = X/X In this case 10/26.98 = n/24.31 giving you 243.1 = 26.98n then divide 243.1/26.98 = n = 9.01
I use this formula with gears on mustangs all the time.
Dam, guess I could have read further up in the thread before answering... Thought I had the first right answer