One a US customary ruler, the increments are usually in eighths or sixteenths of an inch. Few rulers would have increments that are smaller.
inches in customary units
Just a "smidge" under 3 11/16 inches. That's as close as you're going to get it on a ruler based on 1/16th inch increments. (From a graphic artist who has struggled with this one forever.)
A metric ruler is 30 cm in length. This type of ruler is commonly called a metric foot ruler because it is similar in length to a one foot ruler.
You will not find 4.78 inches on a ruler. The graduations for inches are numbered and these are usually subdivided into 10. So 4.78 inches will be a tine fraction short of the eighth division after the 4 inch mark.
They are called measurements. Like witha ruler or stop watch.
The customary ruler uses both inches and centimeters.
a straightedge need not have measuring increments (inches, centimeters, etc.) while a ruler is a straightedge with measuring increments
a ruler
Different rulers will have different increments, so we can't give a definitive answer - however - I would expect the ruler to at least mark off the centimeters with larger lines and then probably use smaller lines as millimeter increments. Some rulers could use even smaller increments such as half millimeters but I've never personally seen any rulers that went for tenths of a millimeter. When I need to get to that kind of precision I always opt for a different measuring tool such as a micrometer.
Usually, yes. They are shown as marks but not numbered. They appear on the metric scale, but it is centimetres (= 10 mm) that are numbered. Up to 30 on a 1 ft ruler, to 15 on a 6" ruler.
Usually on one side they are centimetres (numbered) with millimeters (marked but not numbered). On the other side there are inches (numbered) with eighths or tenths or sixteenths or even thirty-secondths (marked but not numbered).
inches in customary units
a ruler is called "Fürst"
Called a straight edge
A egept ruler is called a Pharaoh
There are 10 milimeters in 1 centimetre. The numbers on a ruler are usually centimeters. The little un-numbered lines that divide up the centimeters mark the milimeters.
Just a "smidge" under 3 11/16 inches. That's as close as you're going to get it on a ruler based on 1/16th inch increments. (From a graphic artist who has struggled with this one forever.)