The width of a pin would typically be measured in millimeters (mm).
Metres, to measure its length or width, square metres to measure its area.
The metric unit used for measuring the width of a fingernail is usually millimeters (mm).
You would use the metric unit of millimeters (mm) to measure the size of a common house fly.
Please specify what you want to measure about the bucket, for example its height, width, circumference, volume, color, albedo, etc.
I would go with millimetres
centimetre
cm
It would be millimetres.
Kilometres
The width of a pin would typically be measured in millimeters (mm).
Metres, to measure its length or width, square metres to measure its area.
The metric unit used for measuring the width of a fingernail is usually millimeters (mm).
a yard stick
meters
You would use the metric unit of millimeters (mm) to measure the size of a common house fly.
The metric unit of the meter would be the appropriate measure of the area of classroom. Calculating area involves multiplying the length (in meters) of the classroom's length and width. Area of the classroom would be in square (^2) meters.