Where is 0.9 cm on a ruler?
Quick Answer
0.9 cm on a ruler is 9 mm past the 0 cm line (the 9 mm mark).
The red marker shows 9 mm position on a metric ruler. This is 9 millimeters (1 cm = 10 mm).
Centimeters on a Ruler
How to read cm on a ruler
A metric ruler is numbered in centimeters (cm): the tallest lines are the whole-centimeter marks. Each centimeter is split into 10 millimeters, so the single medium-length line halfway between two cm marks is 0.5 cm (5 mm), and the nine short lines are the individual millimeter steps. So 1 cm = 10 mm.
- Whole centimeters — the tallest, numbered lines (1, 2, 3 … cm).
- 0.5 cm mark — the taller line in the middle of each centimeter (e.g. 3.5 cm).
- Millimeter steps — the short lines; each is 0.1 cm past the last cm line.
- Reading a value — for 3.5 cm, find the 3 cm line then go to the half mark just after it.
To read a decimal centimeter value, the whole number is the cm line and the first decimal is how many millimeters past it: 3.5 cm → 3 cm + 5 mm. A whole number like 1 cm sits exactly on a numbered line.
Popular cm on a ruler
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