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Scale 1:25 or 1:75 why scale ruler first reading is 0.5m and 1m respectively ?

Scale 1:25 or 1:75 why scale ruler first reading is 0.5m and 1m respectively ?

(OP)
Dear folks

Simple question

Yes I do understand scale ration 1:25 means 1 unit on a map equal to 25 units on a real and scale ration 1:75 means 1 unit on a map equal to 75 units on real

Question my Kent tri scale ruler showing first number for ratio 1:25 as 0.5 m (i.e 50 cm, 500 mm) while first reading for ratio 1:75 as 1 m (100 cm, 1000mm) ?

My confusion for the ratio 1:25 ruler has 25 small tiny line between 0 and next reading means 25 units right ?? if I multiply 25*25 = 625 why scale reads it as 500 mm or 0.5 m????

Same thing for the ratio 1:75 ruler has 20 small tiny lines between 0 and next reading means 20 units right ?? if I multiply 20*75 = 1500 why do I have 1000 mm or 1 m ????

Thank

RE: Scale 1:25 or 1:75 why scale ruler first reading is 0.5m and 1m respectively ?

The scale is marked.

If there are 25 divisions in 500mm then each small division represents 20mm.
If there are 20 divisions in 1000mm then each small division represents 50mm.

RE: Scale 1:25 or 1:75 why scale ruler first reading is 0.5m and 1m respectively ?

The 50 on the 1:25 scale is just an intermediate, and it represents 500 mm. 50 occurs between each metre just for convenience. On this scale, each small division represents 2 mm, and each longer bar represents 10 mm.

On the 1:75 scale, the intermediate is not numbered, but it is there at, again, 500 mm. The 1, 2, 3, etc are metres, and each small division is 5 mm.

You just have to use the scales to get a feel for the divisions.

RE: Scale 1:25 or 1:75 why scale ruler first reading is 0.5m and 1m respectively ?

they are all different. my Alvin metric scale has 100, 200, 250, 300, 400, and 500 and does not have 25 or 75. all starting with 0.

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