You would use square metres (m2) to find the area of a door.
If it's a standard book, the standard units would probably be cm2.
you find the length and width by counting the numbers on the side to find the width and counting the numbers going across to find the length
Length x Breadth x Height
Square root 529 which is 23 m
A square nanometer.
A metric ruler measures in inches and centimeters.
no clue sorry by.
Any metric unit would do. But it might be easier to pick something smaller than the length of the pencil, like a centimeter, or a millimeter.
It's gonna be inches/centimeters.