What does 45 of a inch look like on a ruler?

On a standard ruler, 45 inches would be represented as 3 feet and 9 inches, since there are 12 inches in a foot. You would find the 3-foot mark and then count an additional 9 inches from there. If you are specifically looking for the fractional part, 45/8 inches would be 5.625 inches, which is slightly over 5 and a half inches, or just under 6 inches on a ruler.