They all use the metric unit to measure things (e.g. inches, centimeters, etc.)
As far as I know, I think the difference might be that a yardstick only measures 1 yard. It has 36 inches (which is 3 feet, which is also 1 yard).
A ruler usually is only 12 inches.
A measuring tape is usually 12 feet.
That's what I know.
