Dear ' . $name . ', here you can make your own printable ruler. For the lessons you can use ratio 1:4 and select A4 as your paper size for printing. If the ruler is not showing click one time in the white bare above.
Scale ratio : Change value like 1:4 or any other value, this will refresh the ruler.
PPI : this should be your PPI (pixels per inch) of for your screen. If you know your screen\'s Pixels per inch : insert it. Select your paper size for printing A4 Paper (landscape)A3 Paper (landscape) and make sure you window is large so you can see the full ruler.
As PPI is not always 100% correct you can use the buttons below to adjust the Ruler to real size deminsions if you like. Use a measure ruler on the screen against the Ruler, you can adjust the ruler by mouse clicks untill it fits. Make sure 1:1 30cm lines up with your own ruler.You can also click click and drag on the ruler self to adjust the PPI value.