Question

What does $0.9$cm mean? It is the same as _______ millimetres. We can also say this nine-tenths of a cm. Right?

Answer 1

Hint: Here we will use the correlation between the centimeter and the millimeters by using the relation $1cm = 10m$and convert the given expression centimeter and millimeters and will follow the system of unit’s concept.

Complete step-by-step answer:
We know that the basic relation between centimetres and millimetres.
$1cm = 10mm$
Place the value for the given value –
$1 \times 0.9cm = 10 \times 0.9mm$
Simplify the above equation finding the product of the terms on both the sides of the equation –
$0.9cm = 9mm$
Hence, $0.9$cm is in $9mm$
Yes, we can say this as nine-tenths of a cm or nine-millimeter.
This is the required solution.

Note: It is very important to know the difference between the system of units and the conversional ratios between them. Since if we say length of one it does not make any sense, also length of one centimetre and one metres and one kilometre and it differs a lot.
Always, remember the conversional relations of the different physical quantities and apply them accordingly.