Put a virtual ruler on your image, you can move and rotate the ruler, it allows you to practice how to use a ruler to measure length.
How to use this virtual ruler on image
select your image to be the background
when mouse over the ruler, you can drag it to move
when mouse over the ruler end , you can drag it to rotate
you can download the results of your practice
How to read a ruler
Before you use a measuring ruler, first determine whether it is an inch ruler or a centimeter ruler. Most countries in the world use metric lengths, except for a few contries, such as the United States, which still use imperial lengths.
There are many lines and number marks on the ruler, zero is the start mark, put a ruler on the object, or vice versa, put an object on the ruler, you have to aligin the line of zero to the end of your object, then look at the other end of the object, on wihic line it is aligned, that is the lenght. for inch ruler, If the line is marked 2, it is length of 2 inches, for cm ruler, If the line is marked 5, it is the length of 5 cm.
There are many shorter lines between the main scales, and those are used to divide it, for inch ruler, in the middle of the mark of 1 inch and 2 inches, that line is 1/2 inch, half of inch, counting from 0, that is 1 1/2 inches.
for cm ruler, in the middle of the mark of 1 cm and 2 cm, that line is 0.5 cm, half of cm, which is also 5 mm. counting from 0, that is 1.5 cm.
If you would like convert between meters, feet and inches (m, ft and in), eg. 2.5 meters is how many feet ? 6' 2" is how tall in meter ? try this meters and feet converter, with our fantastic virtual scale ruler, you will find the answer soon.